diff --git a/PKHeX.Core/Legality/Encounters/Verifiers/VerifyCurrentMoves.cs b/PKHeX.Core/Legality/Encounters/Verifiers/VerifyCurrentMoves.cs
index e654f0539..93fda87d2 100644
--- a/PKHeX.Core/Legality/Encounters/Verifiers/VerifyCurrentMoves.cs
+++ b/PKHeX.Core/Legality/Encounters/Verifiers/VerifyCurrentMoves.cs
@@ -715,7 +715,7 @@ void IsHMSource(IList<bool> flags, ICollection<int> source)
             }
         }
 
-        private static bool IsDefogWhirl(int move) => move == 250 || move == 432;
+        private static bool IsDefogWhirl(int move) => move is (int)Move.Defog or (int)Move.Whirlpool;
         private static bool IsCheckInvalid(CheckResult? chk) => !(chk?.Valid ?? false);
         private static bool IsCheckValid(CheckResult? chk) => chk?.Valid ?? false;
 
diff --git a/PKHeX.Core/Legality/Moves/MoveTechnicalMachine.cs b/PKHeX.Core/Legality/Moves/MoveTechnicalMachine.cs
index d0e550825..5aeebbc22 100644
--- a/PKHeX.Core/Legality/Moves/MoveTechnicalMachine.cs
+++ b/PKHeX.Core/Legality/Moves/MoveTechnicalMachine.cs
@@ -124,29 +124,28 @@ private static GameVersion GetIsMachine4HMTransfer(int species, int move, int fo
 
         private static GameVersion GetIsMachine4HM(int species, int move, int form)
         {
+            var dp = Legal.HM_DPPt;
+            for (var i = 0; i < dp.Length; i++)
             {
-                int i = 0;
-                foreach (var m in Legal.HM_DPPt)
-                {
-                    if (m == move)
-                    {
-                        if (PersonalTable.Pt.GetFormEntry(species, form).TMHM[i + 92])
-                            return GameVersion.DPPt;
-                        break;
-                    }
-                    i++;
-                }
-                foreach (var m in Legal.HM_HGSS)
-                {
-                    if (m == move)
-                    {
-                        if (PersonalTable.HGSS.GetFormEntry(species, form).TMHM[i + 92])
-                            return GameVersion.HGSS;
-                        break;
-                    }
-                    i++;
-                }
+                var m = dp[i];
+                if (m != move)
+                    continue;
+                if (PersonalTable.Pt.GetFormEntry(species, form).TMHM[i + 92])
+                    return GameVersion.DPPt;
+                break;
             }
+
+            var hgss = Legal.HM_HGSS;
+            for (var i = 0; i < hgss.Length; i++)
+            {
+                var m = hgss[i];
+                if (m != move)
+                    continue;
+                if (PersonalTable.HGSS.GetFormEntry(species, form).TMHM[i + 92])
+                    return GameVersion.HGSS;
+                break;
+            }
+
             return Legal.NONE;
         }
 
diff --git a/PKHeX.Core/Legality/Tables/Tables4.cs b/PKHeX.Core/Legality/Tables/Tables4.cs
index 90724bb78..3ff2bde0f 100644
--- a/PKHeX.Core/Legality/Tables/Tables4.cs
+++ b/PKHeX.Core/Legality/Tables/Tables4.cs
@@ -148,8 +148,29 @@ public static partial class Legal
             // Defog (DPPt) excluded since it's actually useful -- prefer to fake transfer from HGSS instead of DPPt.
         };
 
-        internal static readonly HashSet<int> HM_DPPt = new(HM_4_RemovePokeTransfer) {(int)Move.Defog};
-        internal static readonly HashSet<int> HM_HGSS = new(HM_4_RemovePokeTransfer) {(int)Move.Whirlpool};
+        internal static readonly int[] HM_DPPt =
+        {
+            (int)Move.Cut,
+            (int)Move.Fly,
+            (int)Move.Surf,
+            (int)Move.Strength,
+            (int)Move.Defog,
+            (int)Move.RockSmash,
+            (int)Move.Waterfall,
+            (int)Move.RockClimb,
+        };
+
+        internal static readonly int[] HM_HGSS =
+        {
+            (int)Move.Cut,
+            (int)Move.Fly,
+            (int)Move.Surf,
+            (int)Move.Strength,
+            (int)Move.Whirlpool,
+            (int)Move.RockSmash,
+            (int)Move.Waterfall,
+            (int)Move.RockClimb,
+        };
 
         internal static readonly byte[] MovePP_DP =
         {
@@ -272,7 +293,7 @@ internal static int[] RemoveMovesHM45(int[] moves)
         /// </summary>
         /// <param name="moves">Current moves</param>
         /// <returns>Preferred move ban list</returns>
-        private static HashSet<int> GetFavorableHMBanlist(int[] moves)
+        private static ICollection<int> GetFavorableHMBanlist(int[] moves)
         {
             // if has defog, return ban list with whirlpool
             return moves.Contains(432) ? HM_HGSS : HM_DPPt;