Thanks all for the feedback. Many good questions and suggestions. I'll supply some more information. I've cooked less than 20 briskets, so I am still very much int he beginning of the learning curve. I used my WSM and the temp was maintained by a GURU. I hadn't set the temp that high but the fire was running hot all night. Turns out a vent had slid open. I had a probe for food temp and wrapped after there was good bark formed, about seven hours and at 164 internal temp checked at a couple places in the flat. Wrapped in foil and lost the probe for the rest of the cook. After three more hours I began probing for tenderness. There was good improvement in tenderness until...gasp...I likely just became impatient by the sounds of things. I cut across the grain having learned that lesson the hard way in the past. The meat was not falling apart and we did enjoy it, just didn't REALLY ENJOY it like good brisket should be. Leftovers went to work where people said good things (what else will they say) and some went into chili. So, maybe the lesson was to be more patient, but I hate that lesson.
By the way, the feedback I get here has always been helpful and I'd like to think has made me a better cook.