Why is ther no formula to figure out port volume?

hi, I've been reading this thread. port velocity and port shape are everything.
the stock and super stock guys cannot have big ports. how ever their heads
flow very well. they use port velocity and port shape to get lots of cylinder fill. as I was told by super flow at one of their semminars, port shape and velocity are most important. high velocity will put more air in. the super stock guys are flying with stock size ports and valve sizes. they use lots of valve lift also. we're talking 1.88/1.60 mopar and 1.94/1.50 gm motors. I figure if a small block stocker can run low 11 sec and same S/S runs in the low 10 sec must be putting a lot of air in the motor. I have also found test pressure makes a big difference! most people test at 28" gives the big numbers!
25 " is more realistic. newer flow benches are set at 25" test pressure.
also, super flow, stated don't get hung up on the big numbers of size and port volume.