[2022] Weapon multipliers

So there are certain multipliers for guns depending where on the body you shoot. I'll be looking specifically at zombies. So in the game files, it says that the Ace's base damage is 99 with .3 to limbs, .6 to spine, and 1.1 to skull. Are these included with hit location finders based on difficulty? In hard, hit location finders are .1 to lower limb, .2 to upper limb, .5 to spine, and 1 to head. Would these be multiplied on top of the multipliers given in the game files? So hitting a zombie's foot would deal 99*.3*.1 to get ~3 damage?

If that's the case, then damage to the head would be 99*1.1*1 and that would be 110. This doesn't make sense because the Ace does not one shot to the head in hard mode. Do hit location finders override multipliers found in game files?