First few days on ICS (soak) were not nearly as good as I used to get on GB. I let it run down to 30% the other day and then turned it off to charge when I went to bed. Both Sunday and yesterday were outstanding on battery. I was unplugged from 3am til 10pm and turned it off with 70% still showing on the battery indicator.
So, if things aren't as good as you think, try turning it off before you charge as well as giving it a few days to "settle in".