Poseidon 300

I have a Cyklon 300 I bought several months ago, got back from being rebuilt
about a month ago. I just received yesterday an IP Gauge that you hook onto
your BC hose and when I turned the air on my 3500 psi tank, it reads 150
psi. I had been told that the IP for this Cyklon, first stage is the model
3070, was set at about 174 psi. I was wondering will the IP change
depending on the pressure in my tank? Will the 174 occur at a lower tank
pressure? I have dove this regulator about three time so far and everything
seems fine. The second stage primary is the metal housing kind, which when
serviced was taken of an early 2305 first stage, and my Octopus is the
yellow plastic with black hockey puck.