For the record. I have had bad main studs from arp with extreme stretch problems. Only a couple. I have also had their best rocker studs break.
I no longer stud mains unless someone insists and then I use Milodon studs.
Try this: Torque the head stud using 30 weight oil. Mark the flat on the nut as a reference point. Now clean off all the oil and do this again using the arp lube and see how many ft lbs it takes to line up that reference point.