It is strictly an issue of terminology. The term "over the back" has come to be interpreted by some that it is illegal for a player in outside position to get a rebound, even if he does so without causing contact. So I think the powers that be in basketball are simply making an effort to get rid of that term and replace it with "on the back" or "push in the back" or something similar, to reduce confusion.
Another term they are trying to get rid of is a foul being called "on the floor," because it is entirely possible to have a shooting foul for a player who is still on the ground. The key is if he has begun his, what they call "habitual shooting motion." They want officials to refrain from using the term "on the floor" and instead simply say "before the shot" or even simply "no shot."