Out of curiosity I did some Googling on cooking frozen pork butts.
Not a lot of good info available!
Here is one reference that says it might take 50% longer to cook frozen pork, and, not to cook it in a slow cooker.
http://www.acrestationmeatfarm.com/pork_cuts.htm
"My roast isn’t thawed completely, but I need to get my meal started. Can I still cook it?
It is safe to cook frozen or partially-frozen pork in the oven, on the stove or grill without defrosting it first; the cooking time may be about 50% longer. Use a meat thermometer to check for doneness. It is best if frozen pork roasts are cooked at an oven temperature of 325 degrees F. Do not cook frozen pork in a slow cooker."
And this one from the Primo Forum is a nice thread including images of a frozen butt cooked low & slow in a ceramic cooker- including this post:
"I have smoked frozen butts before. Never a problem but it does take several hours more to cook. My opinion would be to thaw it in cold water first and save the smoking fuel. JMHO"
This one also shows a neat way to use a temp probe on the frozen butt. Also,he put a mustard/rub on the butt when it reached 65 degrees internal temp. He does not give the weight of the butt. It took him 17 hours in the Primo (not a Cookshack) to cook?.