Need some pro advise....

[JMBT]

Update: it has been 2750 miles since the last go around and everything is staying tight. I checked torque every 100 miles for awhile, then 500, then 1100, and there has been no backing off of the bolts off the 129 ft/lb torque. I still don't have a definite answer as to what went wrong, and that bugs me to no end.
Thought I would share this, (it is scary): I talked a buddy of my brother's about what happened. He has been a Cummins wrench for about 25 years, and has a very good reputation in California. He said when they change a dampner at the shop, they apply blue loctite from the git-go, not oil as Quickserve recommends or antiseize, and (here's the scary part), they put the bolts on with a 1/2" impact AN DON'T CHECK THE TORQUE!!! WTF!!
Anyhow, that takes away any fears I had of streching the threads, if my torque wrench was out of whack by a little.
Also, he said they always reuse the same bolts unless they are damaged, as they are not a one time use bolt.