Nowhere does it say “make sure is at NORMAL OPERATING TEMP” those words aren’t in the service manual (atleast the one I’m using), it’s the upper end of the operating range, for example the coolant can swing from 174F-230F and maybe a little more that’s a temp difference of 56F, you’re telling the the transmission only has a temp difference of 9F do you know how hard it is to do that in real world situations, the manual also says to make sure the vehicle wasn’t doing towing or other heavy driving which implies the fluid can be a lot hotter and still be in the “normal” range, if I had to make an EDUCATED GUESS based on experience 206F-215F is somewhere in the middle, because if the fluid is checked at that temp based on their testing the trans will still operate smoothly at the lower temp and the higher temp, I’m pretty sure the owners manual says to change the oil at 10k miles also the trans fluid and filter is good till 150k miles which would mean that’s the “normal operating life for those fluids” yet everyone (except for a special few) changes all these fluids a lot sooner, I follow the maintenance manual to the letter but I rather run my trans cooler (if you’re gonna drive yours hard you should let it warm up more) because I don’t drive it hard but that’s just me and it’s worked great for me you do whatever gives you the warm and fuzzies