Mine works perfectly (extra high pressure version). When you install it you should be able to turn the screwdriver with your thumb and two fingers. If you encounter more resistance, back it out and be sure everything is straight. You need to have silicone grease on hand and a few 4 x 1.5 o-rings in case you damage the one on the piston.
Where did you get it? Was it a direct order from Huma in the Netherlands? If so, how long did it take to receive it? If not, were you able to order it from within the US?
When you say it works perfectly, I assume it does not creep up (I have regulator creep with my factory regulator)? The extra high pressure version is working in the higher pressures for you without any adverse affects like blowing past o-rings after the regulator? What cal are you shooting with it? What is your standard use reg pressure set to? Is it rock-solid there?
I am about to pull the trigger on one of these, and since I'm shooting .30 cal at 145 bar right now for about 855-860 fps, I was thinking of going with the extra high pressure version as well, vs the standard factory equivelent range.