The AMNPS is always on the bottom rack with plenty of air flow 360°
I've gone so far as to completely remove the chip loader to achieve maximum oxygen flow
Top vent is wide open
I've used a variety of pellets from the ones provided by AMAZEN to some that I've gotten from Academy (for pellet smokers)
With my limited experience with the AMNPS, the only other thing I can add is to be sure your MAZE or Tube is well lit as mummel & Bear said in the two posts above this one.