2 butts came out totally different...

Have you thought of switching the two halfway through the cook? Just a thought.

I don't cook on an electric CS. I have an FEC.

My last cook, this week i done 4 @ 8 lbs eachl, the lower two( cooked fat down)were done in 13 hrs (194*), but the upper2 (fat up)went 19 1/2 hrs to get to 194*. There wasn't much difference in moistness & all 4 had about58% loss. They were purchased @ BJ's .
They had an extra large fat layer w/the skin still on. Each time I cook butts it seems like another adventure??
RT

You didn't mention,so I'll assume:

Either,or neither,were previously frozen.

Both came from same place,time,size,untrimmed,bone in.

Each was over six pounds.

You checked temps in a couple different places with an instaread,when they read about 187º.

You wiggled the bone,and squeezed it for softness at this point.



Like Ribdog says,switch racks and turn them over about 1/2 way through the cook.

You could spray them with some apple juice ,at this point.



I don't switch on the traditional CS,but you could try.

Unless you are cooking at 200º for timing,I'd try 235º.

When done,spray with some apple juice,foil tightly and let set in a dry cooler for a couple hrs.

Hope this helps a little.