Exactly what I thought! I'm glad you tried it. Your the first other than me that has ever mentioned the drain hole as an air supply for the AMNPS. Before trying mods I'd move the AMNPS over the hole. I'm not sure what people are waiting for and why there has been zero discussion on this potential AMNPS air flow solution. I don't have the 2.5 BT or 2. So it doesn't apply to me with the Gen 1. I saw the hole on the back of the Gen 1 and said i wonder how much air is drawn though it. So I put a lighter to it and I couldn't keep it lit. I guess with the Gen 2 and 2.5 the outside hole isn't visible. Out of sight out of mind.
My only thoughts of putting it over the drain hole is that it puts the Maze really close to the heat element and wonder if more pellets will ignite and start smoking along with the lit ones.
Right now, I seem to have plenty of air with Maze on left side and the chip loader pulled out 2" and turned dump side down. Right now I am smoking Jeff Phillips Campfire Chicken with pecan pellets and they are smoking well. It will be done in about 10 more minutes. Since you only smoke it one hr before closing it up, I lit both ends of my Maze and it smoked really-really great. The reason I did this is because I used wood chips in the past and it got heavy smoke for one hr, and the food was perfect, so I wanted to give it a heavy dose the first hr and it worked with both ends of Maze lit and chip dumper out 2" and dump side down.