I would say based on the 4 man leagues I see in my house and the 5 man league that bowls on Monday nights, the percentages are much higher for a 300 game to occur in a 4 man league. I believe in the classic league there have been 3 300 games to date this fall, and in our Monday night league there have been none- 290 has been the highest shot so far.
I think the more that people play the track area in a 5 man league, the more adjustments need to be made to keep the ball on line throughout the night. Or you have to be willing to make ball speed, hand release and/or equipment changes very quickly.
Matt