As to your question, Bill, of our timing (examples of which are posted above, several being at or more than 2hrs/lb) vis-a-vis what one often reads in books is that frankly the books are wrong or unclear.
A large bone-in butt is likely to take around 2hrs/lb if cooked ~225, longer if the temp trends lower (not at all uncommon on an overnight cook where one is not watching the cooker) and shorter if the temp trends or spikes higher periodically (not at all uncommon on an overnight cook where one is not watching the cooker
); butts cooked at ~250 will cook more toward 1.5hrs/lb but the same potential for a shorter or longer cook applies. We all know this and most of us have experienced all sorts of variations in cook times.
Most (but not all!) authors understand the vagaries of barbecue, the ofttimes vagueness of the specifics of actual cooks, and the potential for contributing externalites (like those alluded to above, temp of meat when it went into the cooker, mop use, type and frequency, and several other factors) and often include at least a cursory discussion of these issues in the narrative of the book.
Books written for what are assumed to be 'advanced' readers/cooks might eliminate or merely touch on some of this info. Recipes written by authors who probably don't have any business writing about barbecue probably won't include any of it. However, an author might include all or much of it but the editor might strike much of it too because, unless skillfully included in the narrative, it can clutter the recipe(s) and make too much read as too vague. Most editors do not like this sort of 'clutter' even though it might be necessary for a complete understanding of the subject involved.
One sees this frequently (and not just with barbecue books) from publishing houses or imprints not well versed with publishing cookbooks and from those who pair their authors with literary-minded (rather than food/cooking-minded) editors. This is particularly glaring--and obvious--when a clearly talented and well known chef is scooped by a publisher wanting to capitalize on the fame of the chef but pairs him or her with a clueless editor and then releases a poorly received book.
