My guess is you’re looking at absolute pressure.
The boost sensor on these trucks are 3bar sensors.
14.5x3 = 43.5
But now take into consideration atmospheric pressure; I’m guessing you’re at sea leave so 43.5 -14.5 ~29psi
That’s as high as the boost gauge will read, 29psi.
If you’re looking at psia which doesn’t take into consideration atmosphere, then it’s (relative) boost + 14.5.
So likely you’re actually only making 22psi.
36psi - 14.5 (atmospheric pressure) = 21.5-22psi
Sorry for the long post