Cricket .22 cal Issue

Its a Brand new cricket .22
I Use jsb 18.13 average speed 880fps
Shot about 1500 pellets thru it .

Three days ago I've shot my cricket
it has accuracy issues , chrono it gives me 1051fps , 1056fps, 1045fps, 1044fps, 876fps, 1040
After that I check :
1. Humer striker spring and adjuster are not broken
2. Firing valve spring is not loose
3. The valve(bushing,body , shaft) is not broken (it's a metal valve)

After that I shot it again and have the following chrono result:
876fps, 871fps, 881fps, then again 1040 fps
Is that regulator issue?
Help pls . 

 
I don't know a thing about Crickets but, just as an option i would check the chrono when firing.
Once, i was shooting my Royale through a Chrony (the ones that are collapsible) and because the chrony was just a tiny bit folded the sensors were closer to each other and i was getting readings of 1100+fps! So be careful with that when using foldeable chronographs
 
Exactly what these guys said! If you don't know what your doing with a crono graph it can drive you bonkers! I have a green foldable procrono and it used to drive me crazy! I would get reading all over the place.(I don't have a shade or light kit for it.)

now I only do crono graph work when it's cloudy outside. Presto! No more crazy crono graph numbers. No more fixing guns that aren't broken in the first place.

I have also noticed when the pellet flies right over the outside edge of the sensors it also gives goofy readings.