Well, I fired up the smoker today with mesquite wood. I let her heat up to 400-degrees. Then cooled down to 275-degrees and she held 275 like a champ. I rubbed a couple of chickens (halved) and tossed them on. The temp held rock solid once again. Then, when the heat started to drop, I pulled the birds & added wood, but the temps never came back. She never got above 225-degrees.
I figured the grate was too low and filled up with ash below, which it did. What's got me stumped is the temp never came back but the wood burned off. It actually burned FASTER with less heat.... Which was the exact results as my last test with charcoal 2 weeks ago.
I'm gonna raise the fire grate by 4" and run her up to 250 for as long as she will hold it, and re-stoke and see if the temps will rebound...
Another test and yet something else learned. I figure, 'When I stop learning, they will be throwing dirt in my face....'