I've been messing around with a character build, and I've noticed some weird stuff happening when you delete levels. For instance, I deleted a level of fighter and his bonus feat (dodge) went away; however, it allowed me to pick a feat (mobility) that had that bonus feat as a prerequisite. It also doesn't have Dodge on the feat list any more. Also I deleted all my levels of rogue and then added them back and the skill points were totally wack.