Few people are familiar with, or understand stress-strain curves of Grade 8 material and how it relates to torque-to-yield bolts, especially the long bolts used in M103 and M104 engines. The design engineer who specifies a max stretch limit for these bolts understands that this limit is well below the danger point of necking for the bolt. The people who use these bolts find that the max stretch limit isn't reached until after multiple uses. One benefit of having a measurable limit is to weed out the bolts that may have been torqued more times than expected, due to the mechanic losing his place or distraction during the torquing procedure.

It is the people who don't understand how the stress-strain curve applies to head bolts that make blanket statements of single-use only.