I think there is a problem with this file. I made a mod witch double damage for heavy attack. And it works well by adding damage value in heavy classes.
After that I tried to modify the damage value of light attack (nail baseball bat is realy weak IMO) but it seems to not work. Ingame the damage stay to its initial value.
I notice same think for zombies attack, impossible to tweak their damage (and I need that for a PvZ mod I prepare).
During my tests I noticed something different with this file comparing to the other cpp. I use a source control software (source tree) to check changes made on files and it can't show me the modification that have been done, it tell me that the file is bynarize.
So I wonder if the fact that this file is binary does not prevent the modifications from being taken into account (but takes into account the additions as for the double damage of the heavy attacks).

Side note on the same file : it would be great to have a additionZombiesMeleeMultiplier variable (same as for animals) to not unbalance PvP melee combat by modifying heavy attacks damages.