Fx impact .22 data and settings ?

Hello guys 
I shoot my impact .22 with AA pellets 18.3 grains and they are perfect. 
My settings are
Avg velocity 902 fps
Power on 2 (17,60 mm)
Valve 3 
Regulator 140 bars
I took 90 shoots per fill from 250 to 150 bars. 

Hi , I have the .22 barrell in at the moment and I can't get a good group. I am going to take the suppresor off and see if the pellets are clipping. If I start off with the reg setting at 850 fps and on max at the wheel with the valve setting on 4 and slowly up the reg say every 10 bar , will that work to tell me the correct fps for that pellet. Like I said I am not sure if the pellets are clipping because I can see sometimes that the pellet has gone through the same hole and then it's off by an half inch, and it's on a firm bench rest etc. Hope you can help. John.