I had no idea about these things. Interesting!

Very valuable test, however I think problem is with concept, not with defective item. This is made of silicone which has a low thermal conductivity neither can accumulate heat. So most critical seems to be finding place where thermal sensor is located. You can notice some weird area almost in the middle of pad - this is probably where thermistor is placed. It can't be too close to heating element because then it would read too high temp and mat couldn't reach programmed temp. In this case - unheated area seems to be too large so it needs much more time before desired temp is reached causing heating all mat around much higher. I would start with simple test. Check how long it takes to heat-up mat to 80C, cool it-down and do same test but place some heat radiation insulation - something similar to heated bed insulation mat used in 3D printers. I assume mat will reach programed temperature faster. Next I would place some thin glass and insulation on top with thermocouple between them and see if temp also is rising that much above programmed. I was planning to build my own mat that would work probably much better but since I don't do many cellphones, I decided to buy this one. By looking at your video I'm not sure if that was good choice.

That Is A Cool Tool Or In This Case A Hot One To Bad There Not A Manual Calibration Mode For It Great Info Jay

No regulatory markings, huh? That's a bad sign.