950fps (34gr) with 110-120 bars possible?

I see people saying they are getting 950 fps and over using 34gr pellet/slug with 110-120 bar on their impacts. Mine can't even get close using such a low reg pressure. Am I doing something wrong. The only way to get up to 950 fps with the 34 gr is to crank up my reg to 150 bar. 

My impact is the impact X 2018 version 600mm slug liner A.

I upgraded to the huma dual transfer port. I upgrade stock fx probe to the slug power kit. I upgrade my plenum to the fx mk2 power plenum. Even with all these I have to set my reg to 150 bar to get up to 950 fps. How is it possible that people are getting over 950 fps with 110-120 bar. Are the new impact that much more powerful or what. Even with all my upgrades I can't get that power at that low reg pressure. 
 
What caliber? That comes into play as well.

34gn jsb is .25 cal mk2

On my MK2, I'm at about a 127 reg to hit 920, but if I open up the valve to line 4 and turn my hammer up, it's at 960. 600mm with a slug a liner. 

Wasn't there a change in the valve with the impact x vs mk2? Was before I got into pcps tho, so I'm not sure what other changes the impact went through with earlier models.
 
It is not enough to replace some readily available "upgrade this-and-that" parts from shelfs, you need also a lot of play with springs....

Today I wanted to re-tune my .25 MK2 but I just did only ten shots and stopped, maybe tomorrow I will finish the tune. Anyway

124 bars 948 fps 41 grain ZAN slugs and still about 2mm on HS, but I know that I shall have about 950 with 44 grain. This is a result of tons of trial and errors and tons of tinkering, also re-machining parts and extreme porting.