Smaller cuts of meat can take almost as long as normal sized pieces of meat. Beside there are many variables that can effect the cook so time is not an accurate account of being done. Don't forget to allow a 3-4 hour rest in an insulated cooler before pulling.
The other variable is if you will foil or not foil during the cook. If you foil during the stall, your cooking time will probably be 5 to 7 hours. Without foil it could be 5 to 9 hours.
There is no cookie cutter method of cooking where everything cooks in a specific and then is done at a specific time. The pork butt isn't done until the bone wiggles like a loose tooth, or if boneless, pull or tug on the outer edge if it pulls with no effort it's ready for the rest. You can also probe for tenderness, but I prefer the feel of my fingers over probing.
