diff --git a/mm/src/overlays/actors/ovl_Boss_02/z_boss_02.c b/mm/src/overlays/actors/ovl_Boss_02/z_boss_02.c
index a202805cd..5a9194a8c 100644
--- a/mm/src/overlays/actors/ovl_Boss_02/z_boss_02.c
+++ b/mm/src/overlays/actors/ovl_Boss_02/z_boss_02.c
@@ -534,7 +534,7 @@ void Boss02_SpawnEffectSand(TwinmoldEffect* effects, Vec3f* pos, f32 scale) {
             effects->timer = 0;
             effects->targetScale = 2.0f * scale;
             effects->accel.x = effects->accel.z = 0.0f;
-            effects->justSpawned = true;
+            effects->epoch++;
             break;
         }
     }
@@ -557,7 +557,7 @@ void Boss02_SpawnEffectFragment(TwinmoldEffect* effects, Vec3f* pos) {
             effects->scale = Rand_ZeroFloat(0.04f) + 0.02f;
             effects->rotY = Rand_ZeroFloat(32767.0f);
             effects->rotX = Rand_ZeroFloat(32767.0f);
-            effects->justSpawned = true;
+            effects->epoch++;
             break;
         }
     }
@@ -574,7 +574,7 @@ void Boss02_SpawnEffectFlash(TwinmoldEffect* effects, Vec3f* pos) {
             Math_Vec3f_Copy(&effects->accel, &gZeroVec3f);
             effects->alpha = 255;
             effects->scale = 0.0f;
-            effects->justSpawned = true;
+            effects->epoch++;
             break;
         }
     }
@@ -1573,10 +1573,9 @@ void Boss02_DrawEffects(PlayState* play) {
 
     for (i = 0; i < TWINMOLD_EFFECT_COUNT; i++, effect++) {
         if (effect->type == TWINMOLD_EFFECT_SAND) {
-            // Here and below, set a highbit for effects that just spawned to skip interoplating from an old effect
-            FrameInterpolation_RecordOpenChild(effect, effect->type | (effect->justSpawned ? (1 << 30) : 0));
+            // Here and below, key by effect type merged with epoch
+            FrameInterpolation_RecordOpenChild(effect, (effect->epoch << 4) | effect->type);
             FrameInterpolation_IgnoreActorMtx();
-            effect->justSpawned = false;
             if (!flag) {
                 gSPDisplayList(POLY_XLU_DISP++, gTwinmoldDustMaterialDL);
                 gDPSetEnvColor(POLY_XLU_DISP++, 185, 140, 70, 128);
@@ -1607,9 +1606,8 @@ void Boss02_DrawEffects(PlayState* play) {
     effect = (TwinmoldEffect*)play->specialEffects;
     for (i = 0, flag = false; i < TWINMOLD_EFFECT_COUNT; i++, effect++) {
         if (effect->type == TWINMOLD_EFFECT_FRAGMENT) {
-            FrameInterpolation_RecordOpenChild(effect, effect->type | (effect->justSpawned ? (1 << 30) : 0));
+            FrameInterpolation_RecordOpenChild(effect, (effect->epoch << 4) | effect->type);
             FrameInterpolation_IgnoreActorMtx();
-            effect->justSpawned = false;
             if (!flag) {
                 gDPSetCombineLERP(POLY_OPA_DISP++, SHADE, 0, PRIMITIVE, 0, SHADE, 0, PRIMITIVE, 0, SHADE, 0, PRIMITIVE,
                                   0, SHADE, 0, PRIMITIVE, 0);
@@ -1632,9 +1630,8 @@ void Boss02_DrawEffects(PlayState* play) {
     effect = (TwinmoldEffect*)play->specialEffects;
     for (i = 0, flag = false; i < TWINMOLD_EFFECT_COUNT; i++, effect++) {
         if (effect->type == TWINMOLD_EFFECT_FLASH) {
-            FrameInterpolation_RecordOpenChild(effect, effect->type | (effect->justSpawned ? (1 << 30) : 0));
+            FrameInterpolation_RecordOpenChild(effect, (effect->epoch << 4) | effect->type);
             FrameInterpolation_IgnoreActorMtx();
-            effect->justSpawned = false;
             if (!flag) { //! @bug - dev forgot to set flag to 1, should only apply to first entry?
                 gSPDisplayList(POLY_XLU_DISP++, gLightOrbMaterial1DL);
                 gDPSetEnvColor(POLY_XLU_DISP++, 255, 0, 0, 128);
@@ -1656,9 +1653,8 @@ void Boss02_DrawEffects(PlayState* play) {
     effect = (TwinmoldEffect*)play->specialEffects;
     for (i = 0, flag = false; i < TWINMOLD_EFFECT_COUNT; i++, effect++) {
         if (effect->type == TWINMOLD_EFFECT_BLACK_DUST) {
-            FrameInterpolation_RecordOpenChild(effect, effect->type | (effect->justSpawned ? (1 << 30) : 0));
+            FrameInterpolation_RecordOpenChild(effect, (effect->epoch << 4) | effect->type);
             FrameInterpolation_IgnoreActorMtx();
-            effect->justSpawned = false;
             if (!flag) {
                 gSPDisplayList(POLY_XLU_DISP++, gTwinmoldDustMaterialDL);
                 gDPSetEnvColor(POLY_XLU_DISP++, 30, 30, 30, 128);
@@ -2365,6 +2361,6 @@ void Boss02_Reset(void) {
 
     for (int i = 0; i < TWINMOLD_EFFECT_COUNT; i++) {
         sTwinmoldEffects[i].type = TWINMOLD_EFFECT_NONE;
-        sTwinmoldEffects[i].justSpawned = false;
+        sTwinmoldEffects[i].epoch = 0;
     }
 }
diff --git a/mm/src/overlays/actors/ovl_Boss_02/z_boss_02.h b/mm/src/overlays/actors/ovl_Boss_02/z_boss_02.h
index 37efa665b..9cd4fc52d 100644
--- a/mm/src/overlays/actors/ovl_Boss_02/z_boss_02.h
+++ b/mm/src/overlays/actors/ovl_Boss_02/z_boss_02.h
@@ -23,7 +23,7 @@ typedef struct {
     /* 0x34 */ f32 scale;
     /* 0x38 */ f32 targetScale;
     // 2S2H [Port]
-    /*      */ u8 justSpawned; // Tracks when an effect is spawned for use with interpolation skipping
+    /*      */ s16 epoch; // Tracks when an effect is spawned for use with interpolation skipping
 } TwinmoldEffect; // size = 0x3C
 
 typedef enum {
diff --git a/mm/src/overlays/actors/ovl_Demo_Kankyo/z_demo_kankyo.c b/mm/src/overlays/actors/ovl_Demo_Kankyo/z_demo_kankyo.c
index 6af0792c6..7fd2eef66 100644
--- a/mm/src/overlays/actors/ovl_Demo_Kankyo/z_demo_kankyo.c
+++ b/mm/src/overlays/actors/ovl_Demo_Kankyo/z_demo_kankyo.c
@@ -399,7 +399,7 @@ void DemoKakyo_MoonSparklesActionFunc(DemoKankyo* this, PlayState* play) {
                 }
 
                 if (((this->effects[i].posBase.x + this->effects[i].posOffset.x) - newEye.x) > halfScreenHeight) {
-                    // 2S2H [Interpolation] Here and below, skip particle interpolation on next frame when positionmoves
+                    // 2S2H [Interpolation] Here and below, skip particle interp on next frame when position moves
                     if (ABS(this->effects[i].posBase.x - (newEye.x - halfScreenHeight)) >= 120.0f) {
                         this->effects[i].epoch++;
                     }
diff --git a/mm/src/overlays/actors/ovl_En_Tanron5/z_en_tanron5.c b/mm/src/overlays/actors/ovl_En_Tanron5/z_en_tanron5.c
index e978361df..df1a9b3db 100644
--- a/mm/src/overlays/actors/ovl_En_Tanron5/z_en_tanron5.c
+++ b/mm/src/overlays/actors/ovl_En_Tanron5/z_en_tanron5.c
@@ -182,7 +182,7 @@ void EnTanron5_SpawnEffectSand(TwinmoldEffect* effect, Vec3f* pos, f32 scale) {
             effect->timer = 0;
             effect->scale = scale;
             effect->targetScale = 2.0f * scale;
-            effect->justSpawned = true;
+            effect->epoch++;
             break;
         }
     }
@@ -207,7 +207,7 @@ void EnTanron5_SpawnEffectBlackDust(TwinmoldEffect* effect, Vec3f* pos, f32 scal
             effect->timer = 0;
             effect->scale = scale;
             effect->targetScale = 2.0f * scale;
-            effect->justSpawned = true;
+            effect->epoch++;
             break;
         }
     }
diff --git a/mm/src/overlays/actors/ovl_Object_Kankyo/z_object_kankyo.c b/mm/src/overlays/actors/ovl_Object_Kankyo/z_object_kankyo.c
index 71bbc75fc..7a8222bc9 100644
--- a/mm/src/overlays/actors/ovl_Object_Kankyo/z_object_kankyo.c
+++ b/mm/src/overlays/actors/ovl_Object_Kankyo/z_object_kankyo.c
@@ -281,6 +281,7 @@ void func_808DC454(ObjectKankyo* this, PlayState* play) {
 
                 if (((this->unk_14C[i].unk_00 + this->unk_14C[i].unk_0C) - temp_f24) > temp_120) {
                     this->unk_14C[i].unk_00 = temp_f24 - temp_120;
+                    // 2S2H [Interpolation] Here and below, skip particle interp on next frame when position moves
                     this->unk_14C[i].epoch++;
                 }
 
@@ -455,6 +456,7 @@ void func_808DCDB4(ObjectKankyo* this, PlayState* play) {
 
                 if (((this->unk_14C[i].unk_00 + this->unk_14C[i].unk_0C) - temp_f26) > temp_80) {
                     this->unk_14C[i].unk_00 = temp_f26 - temp_80;
+                    // 2S2H [Interpolation] Here and below, skip particle interp on next frame when position moves
                     this->unk_14C[i].epoch++;
                 }
 
@@ -588,7 +590,6 @@ void func_808DD3C8(Actor* thisx, PlayState* play2) {
             Matrix_Scale(0.05f + tempf, 0.05f + tempf, 0.05f + tempf, MTXMODE_APPLY);
             temp_f2 = Math_Vec3f_DistXYZ(&worldPos, &play->view.eye) / 300.0f;
             temp_f2 = ((1.0f < temp_f2) ? 0.0f : (((1.0f - temp_f2) > 1.0f) ? 1.0f : 1.0f - temp_f2));
-            temp_f2 = 1.59375f;
 
             gDPPipeSync(POLY_XLU_DISP++);
             gDPSetPrimColor(POLY_XLU_DISP++, 0, 0, 255, 255, 255, (u8)(160.0f * temp_f2));
@@ -658,7 +659,6 @@ void func_808DD970(Actor* thisx, PlayState* play2) {
             Matrix_Scale(0.03f, 0.03f, 0.03f, MTXMODE_APPLY);
             temp_f0 = Math_Vec3f_DistXYZ(&worldPos, &play->view.eye);
             temp_f0 = (u8)(255.0f * phi_f26) * (1.0f - (temp_f0 / 300.0f));
-            temp_f0 = 255;
 
             gDPPipeSync(POLY_XLU_DISP++);
             gDPSetPrimColor(POLY_XLU_DISP++, 0, 0, 255, 255, 55, temp_f0);