Yup I feel your pain
I learned to tune from a friend that has been racing for a few years. He is old school and was told to never take a motor over 220f. So he tunes all his motors this way and wonders why he only gets 6min run times and has no power. Well turns out the temp gun we where using was temping 60deg hotter then the motor was.
I now tune by feel and smoke, If I fry a motor then so be it but tell that happens my motors run great and I do 10 to 12 min pits in truggy.
The more I read and learn that normal temps for a race tune is between 200 to 280 for most motors. That temp also changes daily (say motor is tuned perfect in the morning and running 220f may change to 260f by the end of the day)