I believe I was thinking out loud prematurely. The more I think about it, I'm doubting this kind of stress will even show up on the curve.

This makes me think it's as much of a materials property problem as it is pipe stress. If the materials specialist states buys into the new configuration with plastic strain hardening, and new loads with the deformed piping, then you could rationalize keeping the old material.

However, that's admittedly out of my expertise. Perhaps look into the Fitness for Service API standard?