In most cases, for me anyway, the timing has nothing to do with being fouled in the act of shooting. Usually it occurs before the shooting motion begins, so we are waiting to see if A can play through the contact and shoot or pass to an open teammate.
As for comments about late whistles, my favorite is, "Yeah, it was late, but it was right."
Keep in mind that good officiating philosophies require that some calls be made late. Patient and secondary whistles will always be timed a bit differently than the obvious foul in your primary. Strong mechanics and voice go a long way in preventing complaints about late whistles.
You use a strong whistle, close in and vocalize and most times you will hear very little.