I did it on my first pack, and my second. I do not think it matters That much.
As for the previous post, I have not had any problems with rubbing and the load is still transferred to the carry system as I always pack my sleeping bag + sleeping clothes tight in the bottom of the pack --> acts as a lumbar pad if you will. That package is stiff enough to transfer the weight onwards. I have noticed the pack becomes slightly harder to put on, perhaps a bit more wobbly - I have zero problems with the first issue and the second isn't particularly bad either. If anything it actually reminds me to keep a good posture.
Overall, stability depends more on proper fit and packing technique. The plus side? Thinking of the applied forces involved, I think it should work. I've spent some time thinking about it and if you think about how you carry a bulky package it makes sense. It should make the pack lean into your back a bit more, which translates into less back/downward force on the upper shoulder-strap attachment point. But as I've never made two identical packs with different attachment I can't really say.