25 psi is fine for short burst, I'm a little perplexed how your not getting a P1298 code though.
If you hold it there for over eight seconds it may go limpy as most do.
I assume your seeing a boost spike to 25psi then it settles under 22psi? Very normal with a free flowing exhaust if that's the case.
I have posted on this issue in other threads, so wont go into detail here.
Cheers T