Setting all skills to 100 will do that? Huh. Didn't know that.
I haven't done that, no, but I did set a fair number of them to 99 and rolled them to 100 with experience. But about half of them are in the teens still. I'll do some experimenting, anyway, thanks.
XP = skill level gained. Each time a skill progresses from, say, 10 to 11 you gain 11 XP points. From 20 to 21 you would gain 21 points. If you set artificially a skill to 100 you don't gain anything and the level advancing mechanism breaks.