Making calls in other officials area

[lmeadski]

This situation has happened the last two times I have reffed with this official (he has 19 years exp to my one). I am the trail, he's the lead. A1, outside the 3 point line, takes B1 to the hole. I see B1 make contact with A1 on the shot which is a layup attempt. I can see the body contact and blow my whistle. The lead never blows his whistle (maybe because he wasnt going to call anything, or, I am too quick to blow mine). Both times he comments after the game, not directly but interjected into conversation, that I am making calls in his area (implication, let him make the call). In this situation, should I hesitate a bit to see if he calls, and if he doesn't, make the call myself (delayed whistles always draw moans from the crowd and the offending bench), or, do I call it as I see it?