I'm against re-torquing on old setups for a couple reasons but the biggest is that if you've ever dismantled any number of engines and checked the breakaway torque while removing fasteners you'll know that you will NEVER get an accurate and consistent torque across all the bolts without removing them all, chasing threads and properly lubricating them. You cannot do this without most assuredly compromising the HG. Also a quarter turn doesn't equal a flat 10 lbs of axial load and even getting the bolt to budge that little amount will be hell with some of the bolts and too easy with others, so there goes the concept of just giving each a 1/2 turn. If the torque is already inconsistent, increasing the disparity in clamping pressure across the head is not going to help.