Some like to cook at hotter temperatures over a short period of time, while others like to cook at lower temperatures over a longer period of time. The bottom line is you have to find what method works best for you with your cooker, and may not work for someone else.
Even the same person cooking the same size piece of meat will never have an identical cook. The reason no two cooks are alike is due to variances in cookers, type of wood, relative humidity, outside temperature, barometric pressure, and even variances in meat from animal to animal.
As far as internal temperature, every piece of meat is different, I've had some done at 185° where others were done at 205° . Your best results are not determined by temperature alone, but rather by human interaction. Grasp the bone with the thumb and index finger and gently try to twist. If it wiggles like a child's loose tooth, then it is done. If you butt is boneless, simply use a probe, toothpick, or ice-pick and insert it into the meat. When it enters into the meat with almost no resistance, then it's done.
But the pork butt is a very forgiving piece of meat, don't overthink the process and enjoy the cook. Keep us posted....
