We have a higher volume of oil in our house. The people using it have great carry. I haven't bought one, because I am not in the market for a strong ball now. If you have a lower volume of oil, you may need to use a higher grit sand paper or a little polish. It may be losing energy if there is not enough oil.
Since it's already at 4000 grit, you can't sand it any finer, UNLESS
that 4000 is really a 500/4000 surface, then you can go 500/1000/2000/4000 and
you'll get a tiny bit more length. Polish or a 1.5" pin to PAP with a large VAL angle and DRILL angle is probably what's necessary.
In reality, if yo n eed to do all that, you need a more appropriate ball.