Occult Impaction damage (fixes #1641)

- Fixed Occult Impaction damage being double as high as it should be
- In renewal, the skill ratio is now applied to the piercing effect
(If a skill deals 400% damage, the piercing effect will now also be 4 times more effective.)

src/map/battle.c

@@ -3524,7 +3524,7 @@ static int battle_calc_attack_skill_ratio(struct Damage wd, struct block_list *s
 			skillratio += 50 * skill_lv;
 			break;
 		case MO_INVESTIGATE:
-			skillratio += 100 + 150 * skill_lv;
+			skillratio += 75 * skill_lv;
 			break;
 		case MO_EXTREMITYFIST:
 			skillratio += 100 * (7 + sstatus->sp / 10);
@@ -4661,8 +4661,8 @@ struct Damage battle_calc_defense_reduction(struct Damage wd, struct block_list
 	if( def1 == -400 ) /* -400 creates a division by 0 and subsequently crashes */
 		def1 = -399;
 	ATK_ADD2(wd.damage, wd.damage2,
-		is_attack_piercing(wd, src, target, skill_id, skill_lv, EQI_HAND_R) ? (def1/2) : 0,
-		is_attack_piercing(wd, src, target, skill_id, skill_lv, EQI_HAND_L) ? (def1/2) : 0
+		is_attack_piercing(wd, src, target, skill_id, skill_lv, EQI_HAND_R) ? (def1*battle_calc_attack_skill_ratio(wd, src, target, skill_id, skill_lv))/200 : 0,
+		is_attack_piercing(wd, src, target, skill_id, skill_lv, EQI_HAND_L) ? (def1*battle_calc_attack_skill_ratio(wd, src, target, skill_id, skill_lv))/200 : 0
 	);
 	if( !attack_ignores_def(wd, src, target, skill_id, skill_lv, EQI_HAND_R) && !is_attack_piercing(wd, src, target, skill_id, skill_lv, EQI_HAND_R) )
 		wd.damage = wd.damage * (4000+def1) / (4000+10*def1) - vit_def;