new and need help

i have a 03 jetta 1.8t and i just got a stage 2 revo tune that was used and i know the guy personally so i know it’s real my car runs and drives like normal i don’t really do a low gear pull too see if it was really any quicker i just did a couple 5th gear to the floor and let it build boost then let off but it would only make about 12psi and it makes 10psi stock so my question is why is it not making the boost it should and yes i have all the supporting mods dp, cai, bov, and whatever else i just don’t get why it’s barley making anymore boost and not feel much faster