If you hook your arm for leverage around a receiver to make a diving play on the ball, it is a textbook PI. Unfortunately, missing it on one side does not excuse it on the other. This particular technique is called more often than not as well.
I thought that in college they could do that, unless when hooking the arm he caused the WRs body to contort. Also, that play is often not called when the ball is tipped, which i believe t was.
Either way, the refs are inconsistent, to say the least. Pretty bad.