Without this mod installed (until today) I can tell you that washing yourself in the basegame takes longer than washing your clothes and can sometimes get you very, very eaten by zombies if you speed up to do it.

But, to modify that, one would have to find it in the "timed actions" acript or lua (I can't remember the file extension) and tweak it, I would imagine. I saw the file and looked at it briefly for just this reason, but I don't comprehend coding enough. Most I can do is change things in the CD DA and other challenge modes by accessing their hidden lua files. u_u