Your explanation is the closest estimate to my understanding. I was curious how some folks figured it, because it sometimes seems to be an afterthought for pullers, as it was on my MM. I'm hoping for some better power from appropriate CFM and 1/8" more bore next year.
436cu.in. X 1716 / 3456 X 80% = 173cfm
I've probably been running 130cfm at the very most.