First Fly's were I think, only COPS 1 and didn't have the sensitivity option. If you have a mem6 board or later (it will say when you first turn it on) you will have COPS2.
COPS2 works like a dream, so either you have **** paint going through it or it may be in the settings... What is your dwell set at?
Were are the bursts happening? If it is down the barrel it is nothing to do with COPS - more likely, crap paint, or poor paint to barrel match.