Tuning Regulator Set Pressure (internal) vs. Pressure Gauge Reading (external)

Hi Group,

I recently installed a brand new Huma-Air regulator with integrated pressure gauge on my Benjamin Marauder 25 caliber. After successfully installing it I am getting outstanding performance out of it. The regulator is set at 130 BAR with consistent velocities of 842 FPS with the 25.39 grain JSB King pellets. The results are 56 shots (or seven 8 shot mags!) per 3,000 PSI cylinder fill at 40 FPE, it far exceeded my expectations of the famous 40/40 tune that I was going after. I’m not really worried about this question since the performance is outstanding; however, it’s just an observation more than anything.

My question is why does the exterior regulated pressure gauge (it’s a Huma-Air gauge) show ~150 BAR when in fact the regulator is physically set at 130 BAR?

(Note: I have heard new regulators needs to “set” or get broken in?)