At 3 reps, you may also want to take a week off if you find that you have stopped progressing, as you may be burning out your CNS.

Do you know your maximum? If so, what is your sticking point?

There are a shedload of other assistance exercises, that target different areas. Tate presses, Weighted Dips, Close grip Bench, Skull Crushers, and probably a load more Ive forgotten.