I think 150 is the factory setting (set for maximum potential power). It is possible that yours came off the line a little hot. It is also possible that the gauge is inaccurate.
Before I get to the next part, I would ask if the regulator pressure (gauge) is equal to the gun's pressure gauge when the gun pressure is lower than the regulated pressure. For example, when the gun's pressure gauge reads 140 bar, the regulator pressure gauge should also read 140 bar. If they are not equal, one of the gauges is faulty. If they are both equal, it is more likely that your gun was set a little hotter than it should have been. In that case, read on:
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You can lower that pressure. But, there is a process - you need to do it right to avoid damaging the gun.
The impact regulator adjustment can be increased with pressure in the gun. But it can not be lowered with pressure in the gun because it is very bad to screw "against" very high pressure. To clarify, you raise the reg pressure by unscrewing the adjuster screw (located behind the trigger). You lower the regulator pressure by screwing that same screw in - working against the gun pressure.
So, to lower the regulator setting, remove the bottle by unscrewing it (this can be done with pressure in the bottle, as the bottle has its own valving). A small bit of air will escape when you unscrew the bottle (perfectly normal). Then dry fire the gun to remove the air behind the regulator. This will remove the pressure in the gun.
Now you make your screw adjustment to the regulator. Screw it clockwise (lowering the setting) a full turn or two. Then screw the bottle back on, and you will see your new (lower) regulator setting. If it is too low, you can make small (unscrew) turns to raise it to your desired setting. Just remember that you can go "up", but you can't do back "down" if you unscrew it too far. You'll need to remove the bottle and shoot off the regulated air again if you want to do that.
