I spoke to a electrical engineer yesterday about that very thing, his response was basically the accuracy comes from the probe and the precision the controller. He likened it to a mercury thermometer a cheap short thermometer is very accurate because mercury is very sensitive but the precision of the marking is poor and it is no longer correct. He backed up what I feel that typically industry uses a resistive sensor which simply is not very accurate the electronics behind it could be precise but are delivered faulty information or they can be averaging and not be precise but the probe is the first weak link. It is unlikely that a manufacturer would spend the extra cash for a thermal coupler and not back it be good electronics. At least that is what I understood I am not much of an electronic guy so I am a bit sketchy of the details I am just regurgitating what I was told.