I've seen
reviews by Phil and others and they said the temps were fairly accurate out of the box. No mention of funky TCR conversions being necessary.
Even though I haven't measure it with a thermocouple, my experience is the same. It feels about like a
dna-200 (which I also own) as far as accuracy and smoothness of firing in TC mode. For example, I am using SS 430 (TCR .00138) and I entered 1380 into my Drag and it feels the same as my
dna at 450F.
One thing I have noticed, though, is that the device might slightly read the resistance too low. This will make a difference in accuracy,
especially with SS builds. If there is any inaccuracy, I suspect it's with the mod reading the resistance a bit low instead of it being some secret TCR values.