Anyone using a refurbished AV Avenger from PA?

A couple of weeks ago I purchased a refurbished AV Avenger rifle for $249.99 thinking that was a good deal saving me $100.00. The first rifle I received had a bad air leak, I filled it to 300 bar and a couple of hours later it was down to 100 bar so I returned it and exchanged it for another one. The second gun shows signs of use while the first one looked like new but the second one is a awesome shooter. My question is about regulator creep. When I received the gun the regulator was at 2200 psi, I was out shooting the gun today after filling it to 300 bar and noticed the regulator was down to 1900 psi. Is this something I should worry about? My Avenger bullpup is set to 1900 psi and never moves unless I adjust the regulator.
 
In the 14 months I've owned it, my .22 cal refurb has been trouble-free in terms of leaks or regulator creep.

To evaluate yours for regulator creep, fill it to a high-ish pressure (like the 300 bar level you mentioned) and then fire off a couple of shots and note where the regulator pressure settles to after 10 seconds or so. Then set it aside overnight and check the gauge again in the morning.

The scenario described in the original post reads like the opposite of regulator creep.
 
I have one in 22 and one in 25 that I bought as refurbs. They have been great and I haven't had any problems out of them. The 25 had an o-ring failure on the bottom air tube end cap, but I had left it charged up in my truck during some very cold weather this winter. I replaced the tubes with a 580cc carbon fiber bottle and have plans to do the same on the 22 as well. Great guns for the $$ and even more so at refurb pricing. I keep waiting for some 177 refurbs to come back into stock :)