So, my post below (Second Cook/First Butt/Bark Advice Requested) goes into detail regarding my pork butt taking forever and having to finish it in the oven (but getting great reviews for flavor and being quite pretty). While cleaning up, I believe I may have identified the issue. When I cleaned up from my first cook, I simply lifted the coal basket out and emptied it...neglecting to clean up the ash in the bottom of the barrel. Since I started the most recent cook in the dark, I didn't even see the ash when I started this cook - plus there was the whole fiasco about lighting the charcoal with the basket outside the cooker detailed in the other post. :-)
I think perhaps the leftover ash was impeding the proper air flow. We shall see this weekend, once I figure out what to try next.