Fx Impact regulator creep

I wanted to set my .25 cal to shoot at 900 fps so I had the regulator set at 145 with the valve at 4. What i noticed is that when I fill the gun or let it sit around the regulator slowly gets up to 150 bar. So my chrony result would start at 910,905,900,900 and etc. When I took out to the range at 100 yards you definitely see a poi change. Every first shot it slightly up to the left then the remaining 4 shots start going to the right but its still a 2" group. I decide to group really fast and the result were all 1 1/2 " and there is no poi change. So i think i need to turn down the regulator to 135 and speed to 880 to have a better es. Does it seem normal to do that?
 
"BigTinBoat"If you have a regulator that is "creeping" (leaking) turning it down (or up for that matter) will not fix it. You need to stop the creep.
Only when I get the regulator up to 140-150 bar it creeps up. But if its 135 it holds a steady shot string of 880 fps jsb kings. I found that a sweet spot for my impact shooting very tight groups at 100 yards. at 900 fps it opens up just a bit.