diff --git a/src/battle_util.c b/src/battle_util.c
index 10c80a4130..883b0a244d 100644
--- a/src/battle_util.c
+++ b/src/battle_util.c
@@ -7512,24 +7512,6 @@ static inline u32 CalcMoveBasePowerAfterModifiers(struct DamageContext *ctx)
         if (moveType == TYPE_FIRE)
             modifier = uq4_12_multiply(modifier, UQ_4_12(1.25));
         break;
-    case ABILITY_PROTOSYNTHESIS:
-        {
-            enum Stat defHighestStat = GetParadoxBoostedStatId(battlerDef);
-            if (((ctx->weather & B_WEATHER_SUN && HasWeatherEffect()) || gDisableStructs[battlerDef].boosterEnergyActivated)
-             && ((IsBattleMovePhysical(move) && defHighestStat == STAT_DEF) || (IsBattleMoveSpecial(move) && defHighestStat == STAT_SPDEF))
-             && !(gBattleMons[battlerDef].volatiles.transformed))
-                modifier = uq4_12_multiply(modifier, UQ_4_12(0.7));
-        }
-        break;
-    case ABILITY_QUARK_DRIVE:
-        {
-            u32 defHighestStat = GetParadoxBoostedStatId(battlerDef);
-            if ((gFieldStatuses & STATUS_FIELD_ELECTRIC_TERRAIN || gDisableStructs[battlerDef].boosterEnergyActivated)
-             && ((IsBattleMovePhysical(move) && defHighestStat == STAT_DEF) || (IsBattleMoveSpecial(move) && defHighestStat == STAT_SPDEF))
-             && !(gBattleMons[battlerDef].volatiles.transformed))
-                modifier = uq4_12_multiply(modifier, UQ_4_12(0.7));
-        }
-        break;
     default:
         break;
     }
@@ -8036,6 +8018,24 @@ static inline u32 CalcDefenseStat(struct DamageContext *ctx)
         if (gBattleMons[battlerDef].species == SPECIES_CHERRIM_SUNSHINE && IsBattlerWeatherAffected(battlerDef, B_WEATHER_SUN) && !usesDefStat)
             modifier = uq4_12_multiply_half_down(modifier, UQ_4_12(1.5));
         break;
+    case ABILITY_PROTOSYNTHESIS:
+        {
+            enum Stat defHighestStat = GetParadoxBoostedStatId(battlerDef);
+            if (((ctx->weather & B_WEATHER_SUN && HasWeatherEffect()) || gDisableStructs[battlerDef].boosterEnergyActivated)
+             && ((IsBattleMovePhysical(move) && defHighestStat == STAT_DEF) || (IsBattleMoveSpecial(move) && defHighestStat == STAT_SPDEF))
+             && !(gBattleMons[battlerDef].volatiles.transformed))
+                modifier = uq4_12_multiply(modifier, UQ_4_12(1.3));
+        }
+        break;
+    case ABILITY_QUARK_DRIVE:
+        {
+            u32 defHighestStat = GetParadoxBoostedStatId(battlerDef);
+            if ((gFieldStatuses & STATUS_FIELD_ELECTRIC_TERRAIN || gDisableStructs[battlerDef].boosterEnergyActivated)
+             && ((IsBattleMovePhysical(move) && defHighestStat == STAT_DEF) || (IsBattleMoveSpecial(move) && defHighestStat == STAT_SPDEF))
+             && !(gBattleMons[battlerDef].volatiles.transformed))
+                modifier = uq4_12_multiply(modifier, UQ_4_12(1.3));
+        }
+        break;
     default:
         break;
     }
diff --git a/test/battle/ability/protosynthesis.c b/test/battle/ability/protosynthesis.c
index 28188bcf11..f6d55b38a3 100644
--- a/test/battle/ability/protosynthesis.c
+++ b/test/battle/ability/protosynthesis.c
@@ -312,3 +312,38 @@ SINGLE_BATTLE_TEST("Protosynthesis retains its boosted stat after Neutralizing G
         EXPECT_EQ(damage[0], damage[1]);
     }
 }
+
+SINGLE_BATTLE_TEST("Protosynthesis damage calculation is correct")
+{
+    s16 dmg;
+    s16 expectedDamage;
+
+    PARAMETRIZE { expectedDamage = 127; }
+    PARAMETRIZE { expectedDamage = 126; }
+    PARAMETRIZE { expectedDamage = 124; }
+    PARAMETRIZE { expectedDamage = 123; }
+    PARAMETRIZE { expectedDamage = 121; }
+    PARAMETRIZE { expectedDamage = 120; }
+    PARAMETRIZE { expectedDamage = 118; }
+    PARAMETRIZE { expectedDamage = 118; }
+    PARAMETRIZE { expectedDamage = 117; }
+    PARAMETRIZE { expectedDamage = 115; }
+    PARAMETRIZE { expectedDamage = 114; }
+    PARAMETRIZE { expectedDamage = 112; }
+    PARAMETRIZE { expectedDamage = 111; }
+    PARAMETRIZE { expectedDamage = 109; }
+    PARAMETRIZE { expectedDamage = 109; }
+    PARAMETRIZE { expectedDamage = 108; }
+
+    GIVEN {
+        ASSUME(GetMoveCategory(MOVE_CLOSE_COMBAT) == DAMAGE_CATEGORY_PHYSICAL);
+        PLAYER(SPECIES_GOUGING_FIRE) { Ability(ABILITY_PROTOSYNTHESIS); Item(ITEM_BOOSTER_ENERGY); }
+        OPPONENT(SPECIES_URSHIFU_RAPID_STRIKE);
+    } WHEN {
+        TURN { MOVE(opponent, MOVE_CLOSE_COMBAT, WITH_RNG(RNG_DAMAGE_MODIFIER, i)); }
+    } SCENE {
+        HP_BAR(player, captureDamage: &dmg);
+    } THEN {
+        EXPECT_EQ(expectedDamage, dmg);
+    }
+}
diff --git a/test/battle/hold_effect/booster_energy.c b/test/battle/hold_effect/booster_energy.c
index d59c17ef68..9916fe5792 100644
--- a/test/battle/hold_effect/booster_energy.c
+++ b/test/battle/hold_effect/booster_energy.c
@@ -225,7 +225,8 @@ SINGLE_BATTLE_TEST("Booster Energy increases special defense by 30% if it is the
         ANIMATION(ANIM_TYPE_MOVE, MOVE_ROUND, opponent);
         HP_BAR(player, captureDamage: &results[i].damage);
     } FINALLY {
-        EXPECT_MUL_EQ(results[0].damage, Q_4_12(0.7), results[1].damage);
+        EXPECT_MUL_EQ(results[0].damage, Q_4_12(0.77), results[1].damage);
+        EXPECT_MUL_EQ(results[2].damage, Q_4_12(0.77), results[3].damage);
     }
 }