OH BOY MATH!!!!!
At 4000 RPM :
((4000*0.5*0.93*152)*(14.4+10)/14.4)/1758
This would yield 272.5cfm, with an Airflow rate of 19.07 and a PRessure ratio of 1.694.
Now do the same thing at say 6000RPM,you get 408, 28.61, and 1.694.
ok let me see here...
4000*.5=2000, then 2000*.93=1860, ok then 1860*152=282720
OK now 14.4+10= 24.4 , 24.4/14.4 = 1.694444
ok so then 282720*1.694444=479053.33333
now 479053.33333/1758=272.49....
isnt that what i posted?? 
now lets look at the second point...you get 408.64... right at your 410 that you said.. my math isnt wrong... it appears your reading Comprehension might be..LOL.. (thats a joke calm down...) here let me insert a picture
and a quote from their page... (just citing one source)
The pictures above show three different turbocharger cartridges. On the left is the standard T25 found in the 1995-1999 DSM. In the center is the FPT2828 cartridge. Finally on the right is the standard 16g cartridge. The last picture on the right shows the difference in the standard T2 thrust bearing and the severe duty 360 degree thrust bearing used in the FPT2828 turbocharger.
The FPT2828 turbo is a direct boltin upgrade turbo for all 1995-1999 DSM's. It has a compressor mass flow rate of 35 lb/min which depending on who performs the unit conversion from lb/min to CFM is around 510CFM. This is the same flow capacity as the standard 16g turbocharger which is rated at 505 CFM. Looking at the comparison pictures it is possible to tell that the 62 trim T28 compressor wheel is about the same size as the 16g. Checking the dimensions of each wheel also shows this to be true. The 62 trim T28 wheel is actually 0.030" LARGER than the 16g compressor wheel.
Turbo Comparison
So see I'm not blowing smoke up anyones rectum, yes the Super60 Wheel when coupled to the ORiginal Housing and turbine shaft was only good for about 450CFM(at 1BAR.. all turbo manufacturers rate their flow at 1 atmosphere... not 2.5 or whatever), that I am not denying. But the people I mentioned to Chris to source the Turbo from Rate the T28 wheel at 510 CFM when attached to the VNT25 centersection and turbine.. (which would make sense since the VNT has a larger .64 A/R max at the max opening of the vanes.. compared to the smaller .48 A/R's on most super60 Applications)
Anyways.. my math wasn't off.. So,
NANNY NANNY BOOO BOOOOO!!!!!!!!!! 
