I have to be honest (as I always am, sometimes to fault) about this. I never practice from a tree standbecause I don't have that option available to me because of where I live. I do sometimes practice shooting from a sitting position though. I have taken deer from both standing and sitting positions. I can shoot either way.I've only missed one deer shooting from my tree stand while hunting. I don't take questionable shots.
It's just a matter of remembering the rule of thumb, bend at the waist when shooting from a tree stand.