OK...looks like you guys know what you're talking about. I needed more charcoal burning. I was looking at a procedure on the cooking section of this site entitled "Perfect Skin Chicken". The author was able to get the SWM up to 300 degrees with one chimney of coals. This didn't work for me. This time I started with one chimney. The temp got up to 285, but after 15 min started to fall. So I added another 3/4 chimney of lit coals. The temp went up to about 305 and stayed there. Here's the kicker...after 45 minutes, the above mentioned procedure called for basting the chicken with barbecue sauce. I removed the lid and did so. When I replaced the lid the temp went up to 335 degrees! Looks like Jerry N. above nailed it...more air low (move the lid off the rim) ... results in higher temps. I removed my brined and barbecue sauced chicken at 165 degrees internal and it was great. I'm happy, wife happy, what more do you need? Now...on to pork butts, briskets, and who knows...maybe a fatty. Thanks for all your advice...but don't be surprised when you see me here again with another issue.
Ed