I kind of wondered that myself. I was burning BBQERS DELIGHT which had a lot of long ones in it, more crunching in the auger. Now before each cook I vacuum out he ashes and wipe the ramp down.
Last time I cooked, I opened the door to apply sauce which dropped the temp down. This caused more pellets being fed. After ten minutes I shut down and opened the door. There was a good size fire in the firepot and with the door opened flames were being drawn up the ramp towards the auger. I pulled the meat, shut the door and let it cool down.