Under the front -PART 2

[mlancast]

Here's an extension of the previous post that recently happened in my game....
A1 takes a shot. B1 is standing in the lane just under the basket. On the miss, A2 roars over the free throw line and goes up for a massive rebound/dunk. After A2 leaves the floor (Just beyond the charity stripe), B1 takes a couple of steps backwards to get into position to rebound. This causes A2 to make contact with B1 as he attempts the dunk (which is missed -due to the contact?)
A block is called on B1. Needless to say, B's coach goes nuts claiming it should have "over the back" on A2 since he did not go staight up and down. A bang-bang play...
Curious on what you think???????