That part is governed by Play Recognition attributes. so the problem is that PRC is to high in general for mediocre or low level players.As the result it creates appearance of psychic DB's.Sliders also augment that, at 100 PCV on Heisman CPU will recognize the play most of the time , but if you lowered it down to 90-95 it's doesn't happen that often.
I am using PA's as audibles quite frequently and CPU generally falls for them as long i am running them from same formation.And even if it does recognize the pass instead of run (or vice versa) CPU is still in personnel disadvantage in most cases.
Offensively , i noticed that CPU has 2 check points before the snap , one at the beginning of the count and another one in middle of it.
However, if you call say outside man blitz and then audible to cover 3 right before the snap , CPU doesn't make adjustments and generally throws directly at your DB (just an a example).
At least that's my perception....