i would say that 75% of it or higher is the paint..ive had soooo many different guns all properly maintained and ive gone in 1 day just by changing paint--
from +- 4(consistently in the 290s) to +- 15(270 to 300). 1 day same gun different paint
but i have to agree with the OP, your not gonna shoot +- 2 EVERY shot. theres always gonna be some strays and straglers every ten shots or so even with the best paint...most paint is not consistent enough.
my BNIB PM7 got +/- 8 out right away, first shots. I've been using it every weekend for about a month now, and have decently broken in the reg and have adjusted the LPR, and i easily get +/- 4 or 5 with nice paint.
it all depends if the reg and gun are broken in, and how you have tuned your gun.