Trunc just removes the fractional part of a number IE 2.65 would just be 2.
I probably should have prefaced that saying there is no proof those are the actual numbers used on live. Its possible they are but there could still be other factors added in. If i had run into this formula years ago i would have done some serious parsing to find out. I've been tinkering around with them lately, and I can't find any fault in them though. The evasion portion seems to follow a warriors level*10 pretty closely, up until you stop getting defense increases.
http://www.magelo.com/forum/messages...opic=19&page=3