seriously, bench and pushups use just about the same muscles. Seems to me that the main difference is just the learning the muscular coordination for bench. Otherwise, I have no explanation for my results.
you can push more than just your body weight by doing pushups fast or by doing pop ups when you push up. think about it. that's what you are doing anyway when you are doing a pushup. If you were only lifting your body weight, then you'd never go up or down - you'd just stay level.