The problem is you and everyone else are really over thinking this and too trusting in the setting on your thermostat.
You use a non contact thermometer to get your actual reading and fine tune your stat settings to get the surface temps you want.
Its not that hard. You can place it on the outer side of the heat source too.
There is no service needed on the probe and if you use foil tape on your mat then there is no problem removing them for any reason either.
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