Great points Bob! These can definitely affect the moisture and taste results. The time that it took to get to 195 falls pretty closely in line with what others are reporting with the smaller cuts.
It seems that it is becoming a common theme when people smoke smaller cuts of meat. Unfortunately, there just isn't enough mass in the smoker and it affects the results.
You are much better off smoking a 7-10 pound butt, and then freezing leftovers. I think the smallest one I have smoked was around the lower 7ish range and it still turned out good, but I don't think I would try one smaller than that. Based on what we have been seeing here, it seems that when you get down to the 5 pound butts and the 3-5 lb brisket flats that you fight a little bit of an uphill battle to make them come out as well. For a smaller butt, I think I would just take it to 175 degrees and slice it instead of pulling.
Like I said, I haven't bought a smaller one, but my guess is that there isn't as much fat in a smaller one which could also lead to the issue. This would also lend better to slicing.