Hey, I can add up amps draw, and it does make sense. I look at this way t1i without flash 750 photos was my best, pentax k-x without flash 1100 photo. There is no way the A55 comes close to that.
Sure it does, and your results don't surprise me too much, as the T1i only has a CIPA rating of 400 shots using the optical viewfinder (not much better than the A55 you're criticizing for power consumption), and it's CIPA rating with the LCD is only 170 photos.
So, your results getting 750 photos photos sounds about right from it in real world conditons. It doesn't exactly have the highest capacity battery around either (it's worse than most cameras in it's class). ;-)