Thanks a lot, Glenn. That is quite interesting: I have never thought about Osprey packs as external frame. I thought that external frame is when you can see it (you know, the old-style packs). I was not thinking acrobatics, I thought that if the backpack does not hug your back well, then you might get a back pain after several day hike or after climbing over a fallen tree, for example. The Volt is not sold in any stores in my city, so I cannot try it, but I tried Atmos (the men's version of Aura) and, yes, the problem with the hip belt returned. So, probably, men's packs are not for me and I better stick with Aura.
Everyone, thanks a lot for helping me to decide.