T during shot.

[thumpferee]

Situation last night.

I'm L, A1 goes up for a layup (2 feet) opposite block from me. B1 from behind tips the ball, maybe a lil' contact, ball goes to the other side of basket, now 5' from me. As A1 is gathering his own rebound, he yells, "THAT'S A FOUL, COME ON" as he's going up again for a shot, B1 fouls him, "And1".

At this time I'm contemplating a T, and after a few seconds of processing, I felt it warranted.

What I did...As I was going to report the foul, I told my partner to hold on, I have a T coming. I reported the foul, blew my whistle and signaled the T on the now, FT shooter.

How should I have handled this?
Should I have had a T before the shot?
Should I have called the foul and then signaled the T when I decided to do so?