Truss- thats normal for the lvl 10, it needs a higher pressure to operate so once it gets down below a certain point it doesn't shoot. i usually only get 600 - 700 shots on a 3000psi tank which is also normal for a mag or at least its normal for my mag.
Quadster- try going up a carrier size. the longest spring is the softest on paint. you add shims to make it vent sooner.