diff --git a/Templates/Rulesets/ruleset-empty/osu.Game.Rulesets.EmptyFreeform/EmptyFreeformDifficultyCalculator.cs b/Templates/Rulesets/ruleset-empty/osu.Game.Rulesets.EmptyFreeform/EmptyFreeformDifficultyCalculator.cs
index a80f1178b6..34124a022d 100644
--- a/Templates/Rulesets/ruleset-empty/osu.Game.Rulesets.EmptyFreeform/EmptyFreeformDifficultyCalculator.cs
+++ b/Templates/Rulesets/ruleset-empty/osu.Game.Rulesets.EmptyFreeform/EmptyFreeformDifficultyCalculator.cs
@@ -13,7 +13,7 @@ namespace osu.Game.Rulesets.EmptyFreeform
 {
     public class EmptyFreeformDifficultyCalculator : DifficultyCalculator
     {
-        public EmptyFreeformDifficultyCalculator(Ruleset ruleset, WorkingBeatmap beatmap)
+        public EmptyFreeformDifficultyCalculator(Ruleset ruleset, IWorkingBeatmap beatmap)
             : base(ruleset, beatmap)
         {
         }
diff --git a/Templates/Rulesets/ruleset-empty/osu.Game.Rulesets.EmptyFreeform/EmptyFreeformRuleset.cs b/Templates/Rulesets/ruleset-empty/osu.Game.Rulesets.EmptyFreeform/EmptyFreeformRuleset.cs
index 96675e3e99..bd928404d5 100644
--- a/Templates/Rulesets/ruleset-empty/osu.Game.Rulesets.EmptyFreeform/EmptyFreeformRuleset.cs
+++ b/Templates/Rulesets/ruleset-empty/osu.Game.Rulesets.EmptyFreeform/EmptyFreeformRuleset.cs
@@ -30,7 +30,7 @@ namespace osu.Game.Rulesets.EmptyFreeform
         public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) =>
             new EmptyFreeformBeatmapConverter(beatmap, this);
 
-        public override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap) =>
+        public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) =>
             new EmptyFreeformDifficultyCalculator(this, beatmap);
 
         public override IEnumerable<Mod> GetModsFor(ModType type)
diff --git a/Templates/Rulesets/ruleset-example/osu.Game.Rulesets.Pippidon/PippidonDifficultyCalculator.cs b/Templates/Rulesets/ruleset-example/osu.Game.Rulesets.Pippidon/PippidonDifficultyCalculator.cs
index 290148d14b..ef484e27bc 100644
--- a/Templates/Rulesets/ruleset-example/osu.Game.Rulesets.Pippidon/PippidonDifficultyCalculator.cs
+++ b/Templates/Rulesets/ruleset-example/osu.Game.Rulesets.Pippidon/PippidonDifficultyCalculator.cs
@@ -13,7 +13,7 @@ namespace osu.Game.Rulesets.Pippidon
 {
     public class PippidonDifficultyCalculator : DifficultyCalculator
     {
-        public PippidonDifficultyCalculator(Ruleset ruleset, WorkingBeatmap beatmap)
+        public PippidonDifficultyCalculator(Ruleset ruleset, IWorkingBeatmap beatmap)
             : base(ruleset, beatmap)
         {
         }
diff --git a/Templates/Rulesets/ruleset-example/osu.Game.Rulesets.Pippidon/PippidonRuleset.cs b/Templates/Rulesets/ruleset-example/osu.Game.Rulesets.Pippidon/PippidonRuleset.cs
index 89fed791cd..5f463e71f8 100644
--- a/Templates/Rulesets/ruleset-example/osu.Game.Rulesets.Pippidon/PippidonRuleset.cs
+++ b/Templates/Rulesets/ruleset-example/osu.Game.Rulesets.Pippidon/PippidonRuleset.cs
@@ -26,7 +26,7 @@ namespace osu.Game.Rulesets.Pippidon
         public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) =>
             new PippidonBeatmapConverter(beatmap, this);
 
-        public override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap) =>
+        public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) =>
             new PippidonDifficultyCalculator(this, beatmap);
 
         public override IEnumerable<Mod> GetModsFor(ModType type)
diff --git a/Templates/Rulesets/ruleset-scrolling-empty/osu.Game.Rulesets.EmptyScrolling/EmptyScrollingDifficultyCalculator.cs b/Templates/Rulesets/ruleset-scrolling-empty/osu.Game.Rulesets.EmptyScrolling/EmptyScrollingDifficultyCalculator.cs
index f557a4c754..37c2b9f1eb 100644
--- a/Templates/Rulesets/ruleset-scrolling-empty/osu.Game.Rulesets.EmptyScrolling/EmptyScrollingDifficultyCalculator.cs
+++ b/Templates/Rulesets/ruleset-scrolling-empty/osu.Game.Rulesets.EmptyScrolling/EmptyScrollingDifficultyCalculator.cs
@@ -13,7 +13,7 @@ namespace osu.Game.Rulesets.EmptyScrolling
 {
     public class EmptyScrollingDifficultyCalculator : DifficultyCalculator
     {
-        public EmptyScrollingDifficultyCalculator(Ruleset ruleset, WorkingBeatmap beatmap)
+        public EmptyScrollingDifficultyCalculator(Ruleset ruleset, IWorkingBeatmap beatmap)
             : base(ruleset, beatmap)
         {
         }
diff --git a/Templates/Rulesets/ruleset-scrolling-empty/osu.Game.Rulesets.EmptyScrolling/EmptyScrollingRuleset.cs b/Templates/Rulesets/ruleset-scrolling-empty/osu.Game.Rulesets.EmptyScrolling/EmptyScrollingRuleset.cs
index c1d4de52b7..940eaa1a55 100644
--- a/Templates/Rulesets/ruleset-scrolling-empty/osu.Game.Rulesets.EmptyScrolling/EmptyScrollingRuleset.cs
+++ b/Templates/Rulesets/ruleset-scrolling-empty/osu.Game.Rulesets.EmptyScrolling/EmptyScrollingRuleset.cs
@@ -24,7 +24,7 @@ namespace osu.Game.Rulesets.EmptyScrolling
 
         public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) => new EmptyScrollingBeatmapConverter(beatmap, this);
 
-        public override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap) => new EmptyScrollingDifficultyCalculator(this, beatmap);
+        public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) => new EmptyScrollingDifficultyCalculator(this, beatmap);
 
         public override IEnumerable<Mod> GetModsFor(ModType type)
         {
diff --git a/Templates/Rulesets/ruleset-scrolling-example/osu.Game.Rulesets.Pippidon/PippidonDifficultyCalculator.cs b/Templates/Rulesets/ruleset-scrolling-example/osu.Game.Rulesets.Pippidon/PippidonDifficultyCalculator.cs
index 290148d14b..ef484e27bc 100644
--- a/Templates/Rulesets/ruleset-scrolling-example/osu.Game.Rulesets.Pippidon/PippidonDifficultyCalculator.cs
+++ b/Templates/Rulesets/ruleset-scrolling-example/osu.Game.Rulesets.Pippidon/PippidonDifficultyCalculator.cs
@@ -13,7 +13,7 @@ namespace osu.Game.Rulesets.Pippidon
 {
     public class PippidonDifficultyCalculator : DifficultyCalculator
     {
-        public PippidonDifficultyCalculator(Ruleset ruleset, WorkingBeatmap beatmap)
+        public PippidonDifficultyCalculator(Ruleset ruleset, IWorkingBeatmap beatmap)
             : base(ruleset, beatmap)
         {
         }
diff --git a/Templates/Rulesets/ruleset-scrolling-example/osu.Game.Rulesets.Pippidon/PippidonRuleset.cs b/Templates/Rulesets/ruleset-scrolling-example/osu.Game.Rulesets.Pippidon/PippidonRuleset.cs
index ede00f1510..4b1ef7c9a8 100644
--- a/Templates/Rulesets/ruleset-scrolling-example/osu.Game.Rulesets.Pippidon/PippidonRuleset.cs
+++ b/Templates/Rulesets/ruleset-scrolling-example/osu.Game.Rulesets.Pippidon/PippidonRuleset.cs
@@ -24,7 +24,7 @@ namespace osu.Game.Rulesets.Pippidon
 
         public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) => new PippidonBeatmapConverter(beatmap, this);
 
-        public override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap) => new PippidonDifficultyCalculator(this, beatmap);
+        public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) => new PippidonDifficultyCalculator(this, beatmap);
 
         public override IEnumerable<Mod> GetModsFor(ModType type)
         {
diff --git a/osu.Game.Rulesets.Catch/CatchRuleset.cs b/osu.Game.Rulesets.Catch/CatchRuleset.cs
index 93240d312b..c879398d23 100644
--- a/osu.Game.Rulesets.Catch/CatchRuleset.cs
+++ b/osu.Game.Rulesets.Catch/CatchRuleset.cs
@@ -178,7 +178,7 @@ namespace osu.Game.Rulesets.Catch
             return base.GetDisplayNameForHitResult(result);
         }
 
-        public override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap) => new CatchDifficultyCalculator(this, beatmap);
+        public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) => new CatchDifficultyCalculator(this, beatmap);
 
         public override ISkin CreateLegacySkinProvider(ISkin skin, IBeatmap beatmap) => new CatchLegacySkinTransformer(skin);
 
diff --git a/osu.Game.Rulesets.Catch/Difficulty/CatchDifficultyCalculator.cs b/osu.Game.Rulesets.Catch/Difficulty/CatchDifficultyCalculator.cs
index 03a76f10ef..50ddbaba71 100644
--- a/osu.Game.Rulesets.Catch/Difficulty/CatchDifficultyCalculator.cs
+++ b/osu.Game.Rulesets.Catch/Difficulty/CatchDifficultyCalculator.cs
@@ -23,7 +23,7 @@ namespace osu.Game.Rulesets.Catch.Difficulty
 
         private float halfCatcherWidth;
 
-        public CatchDifficultyCalculator(Ruleset ruleset, WorkingBeatmap beatmap)
+        public CatchDifficultyCalculator(Ruleset ruleset, IWorkingBeatmap beatmap)
             : base(ruleset, beatmap)
         {
         }
diff --git a/osu.Game.Rulesets.Mania/Difficulty/ManiaDifficultyCalculator.cs b/osu.Game.Rulesets.Mania/Difficulty/ManiaDifficultyCalculator.cs
index aee3268544..640fdac225 100644
--- a/osu.Game.Rulesets.Mania/Difficulty/ManiaDifficultyCalculator.cs
+++ b/osu.Game.Rulesets.Mania/Difficulty/ManiaDifficultyCalculator.cs
@@ -5,6 +5,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using osu.Game.Beatmaps;
+using osu.Game.Extensions;
 using osu.Game.Rulesets.Difficulty;
 using osu.Game.Rulesets.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Difficulty.Skills;
@@ -28,11 +29,11 @@ namespace osu.Game.Rulesets.Mania.Difficulty
         private readonly bool isForCurrentRuleset;
         private readonly double originalOverallDifficulty;
 
-        public ManiaDifficultyCalculator(Ruleset ruleset, WorkingBeatmap beatmap)
+        public ManiaDifficultyCalculator(Ruleset ruleset, IWorkingBeatmap beatmap)
             : base(ruleset, beatmap)
         {
-            isForCurrentRuleset = beatmap.BeatmapInfo.Ruleset.Equals(ruleset.RulesetInfo);
-            originalOverallDifficulty = beatmap.BeatmapInfo.BaseDifficulty.OverallDifficulty;
+            isForCurrentRuleset = beatmap.BeatmapInfo.Ruleset.MatchesOnlineID(ruleset);
+            originalOverallDifficulty = beatmap.BeatmapInfo.Difficulty.OverallDifficulty;
         }
 
         protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills, double clockRate)
diff --git a/osu.Game.Rulesets.Mania/ManiaRuleset.cs b/osu.Game.Rulesets.Mania/ManiaRuleset.cs
index a9b16c61d4..d7d0fed846 100644
--- a/osu.Game.Rulesets.Mania/ManiaRuleset.cs
+++ b/osu.Game.Rulesets.Mania/ManiaRuleset.cs
@@ -272,7 +272,7 @@ namespace osu.Game.Rulesets.Mania
 
         public override Drawable CreateIcon() => new SpriteIcon { Icon = OsuIcon.RulesetMania };
 
-        public override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap) => new ManiaDifficultyCalculator(this, beatmap);
+        public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) => new ManiaDifficultyCalculator(this, beatmap);
 
         public int LegacyID => 3;
 
diff --git a/osu.Game.Rulesets.Osu/Difficulty/OsuDifficultyCalculator.cs b/osu.Game.Rulesets.Osu/Difficulty/OsuDifficultyCalculator.cs
index 558ddc16ef..892b8da527 100644
--- a/osu.Game.Rulesets.Osu/Difficulty/OsuDifficultyCalculator.cs
+++ b/osu.Game.Rulesets.Osu/Difficulty/OsuDifficultyCalculator.cs
@@ -23,7 +23,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty
         private const double difficulty_multiplier = 0.0675;
         private double hitWindowGreat;
 
-        public OsuDifficultyCalculator(Ruleset ruleset, WorkingBeatmap beatmap)
+        public OsuDifficultyCalculator(Ruleset ruleset, IWorkingBeatmap beatmap)
             : base(ruleset, beatmap)
         {
         }
diff --git a/osu.Game.Rulesets.Osu/OsuRuleset.cs b/osu.Game.Rulesets.Osu/OsuRuleset.cs
index ee4712c3b8..6d50dc0a06 100644
--- a/osu.Game.Rulesets.Osu/OsuRuleset.cs
+++ b/osu.Game.Rulesets.Osu/OsuRuleset.cs
@@ -208,7 +208,7 @@ namespace osu.Game.Rulesets.Osu
 
         public override Drawable CreateIcon() => new SpriteIcon { Icon = OsuIcon.RulesetOsu };
 
-        public override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap) => new OsuDifficultyCalculator(this, beatmap);
+        public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) => new OsuDifficultyCalculator(this, beatmap);
 
         public override PerformanceCalculator CreatePerformanceCalculator(DifficultyAttributes attributes, ScoreInfo score) => new OsuPerformanceCalculator(this, attributes, score);
 
diff --git a/osu.Game.Rulesets.Taiko/Difficulty/TaikoDifficultyCalculator.cs b/osu.Game.Rulesets.Taiko/Difficulty/TaikoDifficultyCalculator.cs
index 7dd47e804b..31d7304184 100644
--- a/osu.Game.Rulesets.Taiko/Difficulty/TaikoDifficultyCalculator.cs
+++ b/osu.Game.Rulesets.Taiko/Difficulty/TaikoDifficultyCalculator.cs
@@ -24,7 +24,7 @@ namespace osu.Game.Rulesets.Taiko.Difficulty
         private const double colour_skill_multiplier = 0.01;
         private const double stamina_skill_multiplier = 0.02;
 
-        public TaikoDifficultyCalculator(Ruleset ruleset, WorkingBeatmap beatmap)
+        public TaikoDifficultyCalculator(Ruleset ruleset, IWorkingBeatmap beatmap)
             : base(ruleset, beatmap)
         {
         }
diff --git a/osu.Game.Rulesets.Taiko/TaikoRuleset.cs b/osu.Game.Rulesets.Taiko/TaikoRuleset.cs
index adc924ba38..e4dea77377 100644
--- a/osu.Game.Rulesets.Taiko/TaikoRuleset.cs
+++ b/osu.Game.Rulesets.Taiko/TaikoRuleset.cs
@@ -168,7 +168,7 @@ namespace osu.Game.Rulesets.Taiko
 
         public override HitObjectComposer CreateHitObjectComposer() => new TaikoHitObjectComposer(this);
 
-        public override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap) => new TaikoDifficultyCalculator(this, beatmap);
+        public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) => new TaikoDifficultyCalculator(this, beatmap);
 
         public override PerformanceCalculator CreatePerformanceCalculator(DifficultyAttributes attributes, ScoreInfo score) => new TaikoPerformanceCalculator(this, attributes, score);
 
diff --git a/osu.Game.Tests/Mods/ModDifficultyAdjustTest.cs b/osu.Game.Tests/Mods/ModDifficultyAdjustTest.cs
index fd620a0e95..85b4688eb9 100644
--- a/osu.Game.Tests/Mods/ModDifficultyAdjustTest.cs
+++ b/osu.Game.Tests/Mods/ModDifficultyAdjustTest.cs
@@ -156,7 +156,7 @@ namespace osu.Game.Tests.Mods
                 throw new System.NotImplementedException();
             }
 
-            public override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap)
+            public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap)
             {
                 throw new System.NotImplementedException();
             }
diff --git a/osu.Game.Tests/Online/TestAPIModJsonSerialization.cs b/osu.Game.Tests/Online/TestAPIModJsonSerialization.cs
index 656e333073..8378b33b3d 100644
--- a/osu.Game.Tests/Online/TestAPIModJsonSerialization.cs
+++ b/osu.Game.Tests/Online/TestAPIModJsonSerialization.cs
@@ -128,7 +128,7 @@ namespace osu.Game.Tests.Online
 
             public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) => throw new NotImplementedException();
 
-            public override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap) => throw new NotImplementedException();
+            public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) => throw new NotImplementedException();
 
             public override string Description { get; } = string.Empty;
             public override string ShortName { get; } = string.Empty;
diff --git a/osu.Game.Tests/Online/TestAPIModMessagePackSerialization.cs b/osu.Game.Tests/Online/TestAPIModMessagePackSerialization.cs
index 0462e9feb5..69e19826fd 100644
--- a/osu.Game.Tests/Online/TestAPIModMessagePackSerialization.cs
+++ b/osu.Game.Tests/Online/TestAPIModMessagePackSerialization.cs
@@ -90,7 +90,7 @@ namespace osu.Game.Tests.Online
 
             public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) => throw new System.NotImplementedException();
 
-            public override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap) => throw new System.NotImplementedException();
+            public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) => throw new System.NotImplementedException();
 
             public override string Description { get; } = string.Empty;
             public override string ShortName { get; } = string.Empty;
diff --git a/osu.Game.Tests/Testing/TestSceneRulesetDependencies.cs b/osu.Game.Tests/Testing/TestSceneRulesetDependencies.cs
index 8c6932e792..bb9b705c7e 100644
--- a/osu.Game.Tests/Testing/TestSceneRulesetDependencies.cs
+++ b/osu.Game.Tests/Testing/TestSceneRulesetDependencies.cs
@@ -79,7 +79,7 @@ namespace osu.Game.Tests.Testing
             public override IEnumerable<Mod> GetModsFor(ModType type) => Array.Empty<Mod>();
             public override DrawableRuleset CreateDrawableRulesetWith(IBeatmap beatmap, IReadOnlyList<Mod> mods = null) => null;
             public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) => null;
-            public override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap) => null;
+            public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) => null;
         }
 
         private class TestRulesetConfigManager : IRulesetConfigManager
diff --git a/osu.Game.Tests/Visual/Gameplay/TestSceneDrawableScrollingRuleset.cs b/osu.Game.Tests/Visual/Gameplay/TestSceneDrawableScrollingRuleset.cs
index 3f10d7892d..e1755b8fc3 100644
--- a/osu.Game.Tests/Visual/Gameplay/TestSceneDrawableScrollingRuleset.cs
+++ b/osu.Game.Tests/Visual/Gameplay/TestSceneDrawableScrollingRuleset.cs
@@ -293,7 +293,7 @@ namespace osu.Game.Tests.Visual.Gameplay
 
             public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) => new TestBeatmapConverter(beatmap, null);
 
-            public override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap) => throw new NotImplementedException();
+            public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) => throw new NotImplementedException();
 
             public override string Description { get; } = string.Empty;
 
diff --git a/osu.Game.Tests/Visual/Gameplay/TestSceneKeyBindings.cs b/osu.Game.Tests/Visual/Gameplay/TestSceneKeyBindings.cs
index 0a39d94027..883b8a1ae0 100644
--- a/osu.Game.Tests/Visual/Gameplay/TestSceneKeyBindings.cs
+++ b/osu.Game.Tests/Visual/Gameplay/TestSceneKeyBindings.cs
@@ -49,7 +49,7 @@ namespace osu.Game.Tests.Visual.Gameplay
             public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) =>
                 throw new System.NotImplementedException();
 
-            public override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap) =>
+            public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) =>
                 throw new System.NotImplementedException();
 
             public override IEnumerable<KeyBinding> GetDefaultKeyBindings(int variant = 0)
diff --git a/osu.Game.Tests/Visual/Gameplay/TestScenePoolingRuleset.cs b/osu.Game.Tests/Visual/Gameplay/TestScenePoolingRuleset.cs
index 17a009a2ce..911fffbe7f 100644
--- a/osu.Game.Tests/Visual/Gameplay/TestScenePoolingRuleset.cs
+++ b/osu.Game.Tests/Visual/Gameplay/TestScenePoolingRuleset.cs
@@ -182,7 +182,7 @@ namespace osu.Game.Tests.Visual.Gameplay
 
             public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) => new TestBeatmapConverter(beatmap, this);
 
-            public override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap) => throw new NotImplementedException();
+            public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) => throw new NotImplementedException();
 
             public override string Description { get; } = string.Empty;
 
diff --git a/osu.Game.Tests/Visual/UserInterface/TestSceneModSettings.cs b/osu.Game.Tests/Visual/UserInterface/TestSceneModSettings.cs
index da0fa5d76d..4bb5e29589 100644
--- a/osu.Game.Tests/Visual/UserInterface/TestSceneModSettings.cs
+++ b/osu.Game.Tests/Visual/UserInterface/TestSceneModSettings.cs
@@ -199,7 +199,7 @@ namespace osu.Game.Tests.Visual.UserInterface
 
                 public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) => throw new NotImplementedException();
 
-                public override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap) => throw new NotImplementedException();
+                public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) => throw new NotImplementedException();
 
                 public override string Description { get; } = "test";
                 public override string ShortName { get; } = "tst";
diff --git a/osu.Game/Beatmaps/DummyWorkingBeatmap.cs b/osu.Game/Beatmaps/DummyWorkingBeatmap.cs
index acfd01a3c8..fcb44c462d 100644
--- a/osu.Game/Beatmaps/DummyWorkingBeatmap.cs
+++ b/osu.Game/Beatmaps/DummyWorkingBeatmap.cs
@@ -69,7 +69,7 @@ namespace osu.Game.Beatmaps
 
                 public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) => new DummyBeatmapConverter { Beatmap = beatmap };
 
-                public override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap) => null;
+                public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) => null;
 
                 public override string Description => "dummy";
 
diff --git a/osu.Game/Rulesets/Difficulty/DifficultyCalculator.cs b/osu.Game/Rulesets/Difficulty/DifficultyCalculator.cs
index 5b4284dc2f..f9855a819f 100644
--- a/osu.Game/Rulesets/Difficulty/DifficultyCalculator.cs
+++ b/osu.Game/Rulesets/Difficulty/DifficultyCalculator.cs
@@ -27,9 +27,9 @@ namespace osu.Game.Rulesets.Difficulty
         private double clockRate;
 
         private readonly Ruleset ruleset;
-        private readonly WorkingBeatmap beatmap;
+        private readonly IWorkingBeatmap beatmap;
 
-        protected DifficultyCalculator(Ruleset ruleset, WorkingBeatmap beatmap)
+        protected DifficultyCalculator(Ruleset ruleset, IWorkingBeatmap beatmap)
         {
             this.ruleset = ruleset;
             this.beatmap = beatmap;
diff --git a/osu.Game/Rulesets/Ruleset.cs b/osu.Game/Rulesets/Ruleset.cs
index b0c3836774..ade763eed8 100644
--- a/osu.Game/Rulesets/Ruleset.cs
+++ b/osu.Game/Rulesets/Ruleset.cs
@@ -222,7 +222,7 @@ namespace osu.Game.Rulesets
         /// <returns>The <see cref="IBeatmapProcessor"/>.</returns>
         public virtual IBeatmapProcessor CreateBeatmapProcessor(IBeatmap beatmap) => null;
 
-        public abstract DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap);
+        public abstract DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap);
 
         /// <summary>
         /// Optionally creates a <see cref="PerformanceCalculator"/> to generate performance data from the provided score.
@@ -240,7 +240,7 @@ namespace osu.Game.Rulesets
         /// <param name="score">The score to be processed.</param>
         /// <returns>A performance calculator instance for the provided score.</returns>
         [CanBeNull]
-        public PerformanceCalculator CreatePerformanceCalculator(WorkingBeatmap beatmap, ScoreInfo score)
+        public PerformanceCalculator CreatePerformanceCalculator(IWorkingBeatmap beatmap, ScoreInfo score)
         {
             var difficultyCalculator = CreateDifficultyCalculator(beatmap);
             var difficultyAttributes = difficultyCalculator.Calculate(score.Mods);