I don't have a problem usually if I double tap my macro that uses focus' target. Maybe a latency issue?

Where I've run into trouble is when my main targets something, then something else and i try to cast on target 2...for some reason the assist or target focus wants to hit the first target instead of the second. I find myself hitting my "follow" key anytime I switch targets and want to make sure all my guys are targetting the right fellow (follow key is a target your focus, follow, assist, stopcasting).