diff --git a/Data/Scripts/011_Battle/005_AI/003_AI_Switch.rb b/Data/Scripts/011_Battle/005_AI/003_AI_Switch.rb
index 3b1e2856a..ada1b6079 100644
--- a/Data/Scripts/011_Battle/005_AI/003_AI_Switch.rb
+++ b/Data/Scripts/011_Battle/005_AI/003_AI_Switch.rb
@@ -173,7 +173,7 @@ class Battle::AI
         next if m.base_damage == 0
         @battle.battlers[idxBattler].allOpposing.each do |b|
           bTypes = b.pbTypes(true)
-          sum += Effectiveness.calculate(m.type, bTypes[0], bTypes[1], bTypes[2])
+          sum += Effectiveness.calculate(m.type, *bTypes)
         end
       end
       if best == -1 || sum > bestSum
diff --git a/Data/Scripts/011_Battle/005_AI/008_AI_Move_Utilities.rb b/Data/Scripts/011_Battle/005_AI/008_AI_Move_Utilities.rb
index 046813c8b..ecfec85b3 100644
--- a/Data/Scripts/011_Battle/005_AI/008_AI_Move_Utilities.rb
+++ b/Data/Scripts/011_Battle/005_AI/008_AI_Move_Utilities.rb
@@ -24,54 +24,6 @@ class Battle::AI
   #=============================================================================
   # Move's type effectiveness
   #=============================================================================
-  def pbCalcTypeModSingle(moveType, defType, user, target)
-    ret = Effectiveness.calculate(moveType, defType)
-    if Effectiveness.ineffective_type?(moveType, defType)
-      # Ring Target
-      if target.hasActiveItem?(:RINGTARGET)
-        ret = Effectiveness::NORMAL_EFFECTIVE_MULTIPLIER
-      end
-      # Foresight
-      if (user.hasActiveAbility?(:SCRAPPY) || target.effects[PBEffects::Foresight]) &&
-         defType == :GHOST
-        ret = Effectiveness::NORMAL_EFFECTIVE_MULTIPLIER
-      end
-      # Miracle Eye
-      if target.effects[PBEffects::MiracleEye] && defType == :DARK
-        ret = Effectiveness::NORMAL_EFFECTIVE_MULTIPLIER
-      end
-    elsif Effectiveness.super_effective_type?(moveType, defType)
-      # Delta Stream's weather
-      if target.effectiveWeather == :StrongWinds && defType == :FLYING
-        ret = Effectiveness::NORMAL_EFFECTIVE_MULTIPLIER
-      end
-    end
-    # Grounded Flying-type Pokémon become susceptible to Ground moves
-    if !target.airborne? && defType == :FLYING && moveType == :GROUND
-      ret = Effectiveness::NORMAL_EFFECTIVE_MULTIPLIER
-    end
-    return ret
-  end
-
-  def pbCalcTypeMod(moveType, user, target)
-    ret = Effectiveness::NORMAL_EFFECTIVE_MULTIPLIER
-    return ret if !moveType
-    return ret if moveType == :GROUND && target.pbHasType?(:FLYING) && target.hasActiveItem?(:IRONBALL)
-    # Get effectivenesses
-    if moveType == :SHADOW
-      if target.shadowPokemon?
-        ret = Effectiveness::NOT_VERY_EFFECTIVE_MULTIPLIER
-      else
-        ret = Effectiveness::SUPER_EFFECTIVE_MULTIPLIER
-      end
-    else
-      target.pbTypes(true).each do |type|
-        ret *= pbCalcTypeModSingle(moveType, type, user, target)
-      end
-    end
-    return ret
-  end
-
   # For switching. Determines the effectiveness of a potential switch-in against
   # an opposing battler.
   def pbCalcTypeModPokemon(pkmn, target_battler)
diff --git a/Data/Scripts/011_Battle/005_AI/054_AI_MoveHandlers_MoveAttributes.rb b/Data/Scripts/011_Battle/005_AI/054_AI_MoveHandlers_MoveAttributes.rb
index 69d7bcdf0..08f568715 100644
--- a/Data/Scripts/011_Battle/005_AI/054_AI_MoveHandlers_MoveAttributes.rb
+++ b/Data/Scripts/011_Battle/005_AI/054_AI_MoveHandlers_MoveAttributes.rb
@@ -904,11 +904,10 @@ Battle::AI::Handlers::MoveBasePower.add("EffectivenessIncludesFlyingType",
   proc { |power, move, user, target, ai, battle|
     if GameData::Type.exists?(:FLYING)
       targetTypes = target.battler.pbTypes(true)
-      mult = Effectiveness.calculate(
-        :FLYING, targetTypes[0], targetTypes[1], targetTypes[2]
-      )
-      next (power.to_f * mult / Effectiveness::NORMAL_EFFECTIVE).round
+      mult = Effectiveness.calculate(:FLYING, *targetTypes)
+      power = (power * mult).round
     end
+    next power
   }
 )
 
diff --git a/Data/Scripts/011_Battle/005_AI/102_AIBattler.rb b/Data/Scripts/011_Battle/005_AI/102_AIBattler.rb
index 39cf3f052..fa7799abe 100644
--- a/Data/Scripts/011_Battle/005_AI/102_AIBattler.rb
+++ b/Data/Scripts/011_Battle/005_AI/102_AIBattler.rb
@@ -193,27 +193,23 @@ class Battle::AI::AIBattler
   end
 
   def effectiveness_of_type_against_battler(type, user = nil)
-    return Effectiveness::NORMAL_EFFECTIVE if !type
-    return Effectiveness::NORMAL_EFFECTIVE if type == :GROUND &&
-                                              has_type?(:FLYING) &&
-                                              has_active_item?(:IRONBALL)
+    ret = Effectiveness::NORMAL_EFFECTIVE_MULTIPLIER
+    return ret if !type
+    return ret if type == :GROUND && has_type?(:FLYING) && has_active_item?(:IRONBALL)
     # Get effectivenesses
-    type_mults = [Effectiveness::NORMAL_EFFECTIVE_ONE] * 3   # 3 types max
     if type == :SHADOW
       if @battler.shadowPokemon?
-        type_mults[0] = Effectiveness::NOT_VERY_EFFECTIVE_ONE
+        ret = Effectiveness::NOT_VERY_EFFECTIVE_MULTIPLIER
       else
-        type_mults[0] = Effectiveness::SUPER_EFFECTIVE_ONE
+        ret = Effectiveness::SUPER_EFFECTIVE_MULTIPLIER
       end
     else
-      @battler.pbTypes(true).each_with_index do |defend_type, i|
+      @battler.pbTypes(true).each do |defend_type|
         # TODO: Need to check the move's pbCalcTypeModSingle.
-        type_mults[i] = effectiveness_of_type_against_single_battler_type(type, defend_type, user)
+        ret *= effectiveness_of_type_against_single_battler_type(type, defend_type, user)
       end
+      ret *= 2 if target.effects[PBEffects::TarShot] && type == :FIRE
     end
-    # Multiply all effectivenesses together
-    ret = 1
-    type_mults.each { |m| ret *= m }
     return ret
   end
 
@@ -282,30 +278,30 @@ class Battle::AI::AIBattler
   private
 
   def effectiveness_of_type_against_single_battler_type(type, defend_type, user = nil)
-    ret = Effectiveness.calculate_one(type, defend_type)
+    ret = Effectiveness.calculate(type, defend_type)
     if Effectiveness.ineffective_type?(type, defend_type)
       # Ring Target
       if has_active_item?(:RINGTARGET)
-        ret = Effectiveness::NORMAL_EFFECTIVE_ONE
+        ret = Effectiveness::NORMAL_EFFECTIVE_MULTIPLIER
       end
       # Foresight
       if (user&.has_active_ability?(:SCRAPPY) || @battler.effects[PBEffects::Foresight]) &&
          defend_type == :GHOST
-        ret = Effectiveness::NORMAL_EFFECTIVE_ONE
+        ret = Effectiveness::NORMAL_EFFECTIVE_MULTIPLIER
       end
       # Miracle Eye
       if @battler.effects[PBEffects::MiracleEye] && defend_type == :DARK
-        ret = Effectiveness::NORMAL_EFFECTIVE_ONE
+        ret = Effectiveness::NORMAL_EFFECTIVE_MULTIPLIER
       end
     elsif Effectiveness.super_effective_type?(type, defend_type)
       # Delta Stream's weather
       if @battler.effectiveWeather == :StrongWinds && defend_type == :FLYING
-        ret = Effectiveness::NORMAL_EFFECTIVE_ONE
+        ret = Effectiveness::NORMAL_EFFECTIVE_MULTIPLIER
       end
     end
     # Grounded Flying-type Pokémon become susceptible to Ground moves
-    if !@battler.airborne? && type == :GROUND && defend_type == :FLYING
-      ret = Effectiveness::NORMAL_EFFECTIVE_ONE
+    if !@battler.airborne? && defend_type == :FLYING && type == :GROUND
+      ret = Effectiveness::NORMAL_EFFECTIVE_MULTIPLIER
     end
     return ret
   end
diff --git a/Data/Scripts/011_Battle/005_AI/103_AIMove.rb b/Data/Scripts/011_Battle/005_AI/103_AIMove.rb
index 3e3c89593..78efc12d1 100644
--- a/Data/Scripts/011_Battle/005_AI/103_AIMove.rb
+++ b/Data/Scripts/011_Battle/005_AI/103_AIMove.rb
@@ -322,7 +322,7 @@ class Battle::AI::AIMove
 
     # Type effectiveness
     typemod = target.effectiveness_of_type_against_battler(calc_type, user)
-    multipliers[:final_damage_multiplier] *= typemod.to_f / Effectiveness::NORMAL_EFFECTIVE
+    multipliers[:final_damage_multiplier] *= typemod
 
     # Burn
     if @ai.trainer.high_skill? && user.status == :BURN && physicalMove?(calc_type) &&