I have noticed something similar to what you experienced. I cook on a Backwoods PIglet and Fatboy.
When I use IBP butts, either from Sams or my food service company, I can damn near count on them
being done in 12 hours. I cook at 225* and the butss weigh 7-8 pounds. When I buy the individually
wrapped butts of the same size from a local grocer, it may take 20+ hours for the bone to pull.

My assumption is this: the butts have been frozen and thawed more than once. Only an assumption.

There is always something to be said for having a plan B. And NO, I don't mean hot dogs....

I always try to look at things from when you want to eat. it's kinda like a countdown. If
we're gonna eat at 5:00pm, then the pork shoulders wil need to be done about 3:00 so they can
rest. now count backwards from 3:00 to figure out when you need to start cooking. I always rub up
my shoulders with some rub about 12 hours before, so add 12 hours prior to that. For cooking, you
might have to take into account you're experience with the charcoal that you are using, the
weather, how much meat you have to smoke, how full your BGE is, etc... All of these things will
have an effect on your cooking time, assuming that you are holding a good temp in the egg. So, If I
want to eat at 5:00, I will need to take a good look and make a decision about mid morning. If temp
is now close to the 180 degree range, then Bob's your Uncle and you can take em off at 3:00 and
wrap in foil and put in an insulated ice chest. However, if at say 11:00 I have an internal temp of
170 or below, I really haven't plateaued yet, and it is decision time. Crank the heat? yes,
this will work, but Murphy still has some say here. If I'm faced with this decision, I'll
take em off, wrap in foil, and put in a 250-300 degree oven, where a couple of things will happen.
1. you'll continue to cook, and 2. the steam will be trapped by the foil, aiding with the
desolving of the colagens. at the desired temp, turn the oven off, and let it sit there, or move to
an insulated cooler. This will NOT affect your finished product. Once you pull it, you'll have
a hard time keeping everyones fingers out of there anyway.

I will always have be ready to eat when the appointed time comes. Nobody will leave my house
hungry. and it will be great.

The point is, there are other techniques that will make you successful. In your case, maybe it was
a faulty temp probe. I keep an instant read on hand for that purpose. or maybe it just wasn't
ready using the technique you were using. Then it is time to change the game plan just a bit, to
get ready for your 5:00 dinner. You can do it. just pay attention to what is going on through out
your cook, and make the adjustments.

Murphy does not come to my house anymore, because I always have a plan B or even a plan C. He tries
to crash the party once in a while, but has not been successful.

Take what you learn every time you cook. apply to the next time and the next. You'll have this
down in no time. It is pretty hard to fail using the BGE, but one thing is constant, you'll
always learn something.

I put a couple 7.25 #ers on SUNDAY MORNING around 2 am. At 10 AM, the fire was going down. Due to
some Cr@P lump from our local grocery store, HEB, made in Argentina, I reloaded with the same junk
(to get rid of it), and got the fire back up. I was cooking LOW on purpose (~205). Around 1:30 PM,
I was about 160 and I kicked it up to around 225°. At 6, they hit the target. I pulled, foiled and
stored them in the cooler.

My experience was a combination of bad charcoal, and changing the temp, since I wasn't in a
rush.

7.25 should have taken ~14.5 hours, but that's based on 225-250, IMO. This took me about 16
hours because I was lower, so I figure I did right...

This was all done with a GURU, BONE IN, and making sure that the probes were away from the bone.

Depending on how much fat and gristle...butts can run 1-3 hours per pound when cooking at 250deg
+-......

so 8lbs with a lot of fat at gristle could take 20 hours..but another thing to consider is ....were
they inhanced?..If so you can have 12% solution added to the butts....

And this could cause a longer cook if you took them out of a fridge that had the meat at 40 deg....