DV, change both X-feed valves IAW which UTI? You stated earlier that it would be a simple mod to fit the thermocouple, so why a UTI would be issued I’m not too sure. Also, why change both? A ground run would show which one is leaking.
I can see a case for these thermocouples being fitted, just not too convinced about their usefulness.
By the way, no such thing as a simple mod.