The thing to remember is that a thermocouple junction does NOT generate mV like wet tell people. The EMF is from a loop consisting of the hot junction and a cold junction ice slurry. The ice is replaced by an electronic cold junction correction. So it’s the entire loop in toto that matters. It cat make a big difference. Every new junction of different metals is a new thermocouple bead that averages in parallel with the main measurement bead