if i want to change a perk lets say the SWAT so that its magazine size increase only applies to SWAT weapons how could i do that?

i tried to modify the zedternal.u file and changed this:

static simulated function ModifyMagSizeAndNumberPassive( out float magazineCapacityFactor, int upgLevel)
{
magazineCapacityFactor += default.MagSize * upgLevel;
}

under the line:

Class WMUpgrade_Perk_SWAT extends WMUpgrade_Perk;

into this:

static simulated function ModifyMagSizeAndNumberPassive( out float magazineCapacityFactor, int upgLevel)
{
if (IsWeaponOnSpecificPerk( MyKFW, class'KFgame.KFPerk_SWAT') || IsDamageTypeOnSpecificPerk( DamageType, class'KFgame.KFPerk_SWAT'))
magazineCapacityFactor += default.MagSize * upgLevel;
}

but it didnt work and it didnt change anything even when i completely delete the code the changes dont apply to my game.