Well, I got it up and running, and FSX doesn't seem to be doing anything untoward with the airplane. I've only flown a 152 and not a 172, but the 172 in FSX behaves more or less as I would expect. The wind does push you around a bit in real life. In the real airplane, though, the yoke moves with the airplane, you feel it, and you have a natural tendency to cancel this as soon as you sense it, which is somewhat faster than you can SEE it. At least it was natural for me, your reflexes may vary. Anyway, in FS you can't feel the wind push you, so you wait for a visual cue, which takes longer. I would assume that's why you're so badly affected. It'd be kinda like being "behind the airplane" in the real world. That's all just me guessing though. I don't even have my PPL yet. I didn't get it to bounce me 700 feet, but I didn't have time to put much work into it, just a few bounces around the patch. I have to work tomorrow. (:()

Like i said earlier, i experienced this updraft in fs9 in the portland scenery addon so this is not an effect limited to fsx. It was interesting indeed to just be lifted straight up regardless of the angle of my elevators. It was like i was on an elevator...no pun intended ;)