Charge/Block contact

[Ref in PA]

I am pretty sure I got this right, but want to know your opinion.

A1 has the ball on the wing about foul line extended. A2 is at the top of the key and breaks toward the basket, moving around a screen set by A3. The entry pass to A2 is high and A2 leaps high in the air and secures the ball. B4, seeing the play, sets up in the path of A2 around the second lane position (out from underneath the basket). A2 lands on one foot and continues toward the basket taking a step with the other foot (although not a hugh step). With the second step, A2 contacts B4, knocking B4 to the floor. This was a bang-bang play and B4 did not establish position until A2 was in the air.

Because A2 had control of the ball, I called a charging foul on A2. However, if A2 were just cutting to the basket without the ball, I probably could have called a block on B4 because I did not think A2 would have had time and distance to react (due to the timing of B4 establishing position in the path of A2).

If I did get this right, I thank the board for previous threads that have helped me understand this play. I remember comments and a youtube video.