I've been following this thread and have been hesitant to jump in. .
Set aside the causes of green wood, dirty burn, stale air flow early in smoke, ash covering the meat either from heavy deposits below the grate getting picked up by the airflow, or too vigorously knocking ash off the coals mid-smoke. I've never removed bark. I've used both store bought wood and wood from the white oak tree in my back yard, some of which was probably aged only 6 months early on. And I've used the top vent to bring down temps both early and late in a smoke with no bad results. Basically, I've committed every smoking sin you can. My wife is a supertaster and I just asked her if we've ever had a meat I smoked/cooked that tasted like lighter fluid or creosote and her answer was the same as mine: no.
Now, all that said, to the OP I say go smell your bag of RO lump. I was hesitant to jump in because I don't want to start a charcoal preference war, but I have one bag of RO Lump charcoal in the garage I have been hesitant to use because it has a lighter fluid or paint-like smell. The other bag of RO I bought at the same time smelled like burnt wood. This bag has been sitting unused for almost a year and a half because the odor was noticeable as soon as I opened the bag. My spider sense said pass and I have. The smell is less now than it was originally, but it is still there. I just went and checked.
Finally, don't sweat the temp swings on a butt/shoulder. That piece of meat can take any temp you throw at it as long as it is in the safety zone, even 100F swings. Swings mess with your timing but I've yet to meet a pork butt that could tell time.
Edited by Noboundaries - 5/25/15 at 1:57pm