diff --git a/osu.Game.Rulesets.Mania/ManiaDifficultyCalculator.cs b/osu.Game.Rulesets.Mania/ManiaDifficultyCalculator.cs
index 62d2929f27..e1d3b6212f 100644
--- a/osu.Game.Rulesets.Mania/ManiaDifficultyCalculator.cs
+++ b/osu.Game.Rulesets.Mania/ManiaDifficultyCalculator.cs
@@ -9,7 +9,7 @@ using System.Collections.Generic;
 
 namespace osu.Game.Rulesets.Mania
 {
-    public class ManiaDifficultyCalculator : DifficultyCalculator<ManiaHitObject>
+    internal class ManiaDifficultyCalculator : DifficultyCalculator<ManiaHitObject>
     {
         private const double star_scaling_factor = 0.018;
 
@@ -18,12 +18,12 @@ namespace osu.Game.Rulesets.Mania
         /// This is to eliminate higher influence of stream over aim by simply having more HitObjects with high strain.
         /// The higher this value, the less strains there will be, indirectly giving long beatmaps an advantage.
         /// </summary>
-        protected const double strain_step = 400;
+        private const double strain_step = 400;
 
         /// <summary>
         /// The weighting of each strain value decays to this number * it's previous value
         /// </summary>
-        protected const double decay_weight = 0.9;
+        private const double decay_weight = 0.9;
 
         /// <summary>
         /// HitObjects are stored as a member variable.
@@ -40,7 +40,7 @@ namespace osu.Game.Rulesets.Mania
             // Fill our custom DifficultyHitObject class, that carries additional information
             difficultyHitObjects.Clear();
 
-            int columnCount = (Beatmap as ManiaBeatmap).TotalColumns;
+            int columnCount = (Beatmap as ManiaBeatmap)?.TotalColumns ?? 7;
 
             foreach (var hitObject in Beatmap.HitObjects)
                 difficultyHitObjects.Add(new ManiaHitObjectDifficulty(hitObject, columnCount));
diff --git a/osu.Game.Rulesets.Mania/Objects/ManiaHitObjectDifficulty.cs b/osu.Game.Rulesets.Mania/Objects/ManiaHitObjectDifficulty.cs
index e8b47092f6..0b5e7d7e4c 100644
--- a/osu.Game.Rulesets.Mania/Objects/ManiaHitObjectDifficulty.cs
+++ b/osu.Game.Rulesets.Mania/Objects/ManiaHitObjectDifficulty.cs
@@ -6,7 +6,7 @@ using System;
 
 namespace osu.Game.Rulesets.Mania.Objects
 {
-    class ManiaHitObjectDifficulty
+    internal class ManiaHitObjectDifficulty
     {
         /// <summary>
         /// Factor by how much individual / overall strain decays per second.
@@ -19,7 +19,7 @@ namespace osu.Game.Rulesets.Mania.Objects
 
         internal ManiaHitObject BaseHitObject;
 
-        private int beatmapColumnCount;
+        private readonly int beatmapColumnCount;
 
 
         private double endTime;
@@ -68,7 +68,6 @@ namespace osu.Game.Rulesets.Mania.Objects
         internal void CalculateStrains(ManiaHitObjectDifficulty previousHitObject, double timeRate)
         {
             // TODO: Factor in holds
-            double addition = 1.0;
             double timeElapsed = (BaseHitObject.StartTime - previousHitObject.BaseHitObject.StartTime) / timeRate;
             double individualDecay = Math.Pow(INDIVIDUAL_DECAY_BASE, timeElapsed / 1000);
             double overallDecay = Math.Pow(OVERALL_DECAY_BASE, timeElapsed / 1000);
@@ -106,9 +105,9 @@ namespace osu.Game.Rulesets.Mania.Objects
             heldUntil[BaseHitObject.Column] = endTime;
 
             // Increase individual strain in own column
-            IndividualStrain += (2.0/* + (double)SpeedMania.Column / 8.0*/) * holdFactor;
+            IndividualStrain += 2.0 * holdFactor;
 
-            OverallStrain = previousHitObject.OverallStrain * overallDecay + (addition + holdAddition) * holdFactor;
+            OverallStrain = previousHitObject.OverallStrain * overallDecay + (1.0 + holdAddition) * holdFactor;
         }
     }
 }