Partner coverage

[The whistle]

I need some advice. Last night I worked a HS JV Boys game that was REALLY a good contest. Both teams up and down the court with lots of scoring. My problem was that when the offense did slow it down to a half court game my Partner insisted on watching my area and there were times (about 5) when we would have double whistles outside of the lane area. It was more noticable when my Partner was the lead and he would make a call across the lane below the free throw line, right in front of me. It's not like the calls weren't fouls but I had made the call as well and it occurred in my area. I know that he wasn't watching his area much if he's watching mine. My problem is how do you talk to a guy about making calls out of his Primary? I have worked with him on a previous game and, thinking back, we had some double whistles in that game as well. We both work higher level games too although he has at least a dozen more Varsity games than I do. I will welcome your advice/comments.