The retro valve works on pressure differential between input(tank) and chamber. A level 10 chamber has more residual pressure left after a shot, so the pressure differential is less and therefore results in less force pushing on the on-off pin to reset the trigger. You can still achieve good results though, with the right setup.
A full tank will make all the difference. It will allow maximum air flow through the tank regulator and therefore through the mag valve. Air flow is just as important as pressure when it comes to having a reactive valve.
Except for the Automag in front, its usually the man behind the equipment that counts.