Can anyone explain?

TurboXS did state that the 168.4 hp is at 5731 rpm, but at 12.1 psi, which is lower than stock max psi. Or does the max psi come after the max whp? So then max whp comes at a lower psi than max...doesnt seem efficient. Are my numbers off?

Evo chp maxes at 6500 rpm, reaches max boost of 18.8 psi at 4100 rpm, slowly coming down to 16.1 by redline, which is 7000 rpm. This makes more since, because at 6500 rpm the boost is still upthere. Makes sense, because of the bigger turbo.