Trying to lower Ump45 damage

[Onetimeuser]

Hey. So few weeks ago, we started our own 4d1 server which has became kinda popular. Now we're wondering on how to lower ump damage since it's heavily overpowered. I read the tutorial regarding modifying weapon stats, but no matter how I type the code, ump damage stays the same in game. This is what my currect damage gsc looks like (the important part):

Callback_PlayerDamage_internal( eInflictor, eAttacker, victim, iDamage, iDFlags, sMeansOfDeath, sWeapon, vPoint, vDir, sHitLoc, psOffsetTime )
{

	if ( getDvar("g_gametype") == "oitc" && sWeapon == "turret_minigun_mp" || getDvar("g_gametype") == "gg" && sWeapon == "turret_minigun_mp" || getDvar("g_gametype") == "ss" && sWeapon == "turret_minigun_mp" )
	{
		iDamage = 0;
	}
	if(isSubStr(sWeapon, "ump45_")) // if you want the weapon to do the damage no matter which attachments
	
		iDamage = 1;
	
	if ( !isReallyAlive( victim ) )
		return;

So, I download my server's iw_25.iwd, change it to .zip, extract it, modify the .gsc file like that and then reverse the progress and upload it back. Nothing happens, the damage stays the same.

I also noticed that there's a separate _damage.gsc file in a different folder, but replacing that doesn't help neither.

I tried searching, but none of the threads I came across really proved to be much help.

Thanks, onetimeuser.