What is with these xp levels? When I killed the demonknight I got 11,750 Xp or thereabouts, but I heard he was worth 15,000XP. Also on isle of the werewolves after I cleaned out the ship killing wolfweres didn't give me as much XP as it used to. My party was about 6th - 7th level, except for Imoen, who was level 8/9

I dunno 'bout the werewolves but 11,500 is def the right amount for demon knight. You get 15,000 for killing something else a bit later on though ;) .
Have you tried a higher diff setting? - this might be it?

If you decrease the diff-level, you will get less XP. If you chosse the easiest diff-level, you will get only half the normal XP.

Another EXP rule is that if you kill someone when they're not hostile to you, you only get 10% of their full EXP amount--although this doesn't really apply to the Demonknight or the Werewolves, it's helpful to know.

Thanx...Maybe the figures I read on the web were skewed...forget what difficulty setting my game is on...it's nly my 1st time through