You have to remember. All the testing (A.F.A.I.K.) having lumps no lumps, larger valves, small valves, boss, no boss,etc, were done on a N/A engine, the results will be different when you have air/fuel being forced into the chambers via turbocharger.
On a N/A engine a good flowing cylinder is crucial to making good power, not as much when forced induction is concerned.
Example, on a N/A engine, if you port too much on a 250 head, making all the ports huge, the air velosity slows down so much, you will loose low end torque & pretty much everywhere else in the RPM range.
If you do the same to a 250 head & slap a blower on top, the engine will make more power as long as you have a big enough supercharger. Bigger ports, bigger windows, allows more air/fuel in. It is more forgiving.
A guy did some porting on some Vortec V-6 heads (for a Syclone), flow tested before & after, the after porting flow test results were worse than what the factory stock head flowed, yet he still installed these ported heads on that flowed worse than stock & his Syclone ran faster,, just saying when forced induction is concerned head flow numbers are not as critical.
