Hmm, wonder why I see the similiar temp changes as those with the hotline or the probe in the pan. If you were correct, I should see no fluctuation in temps. And then there was the 20 degree drop I saw when I changed my fluid. What is your explanation for the changes I see if the port is dead ?
I don't know how and when these temps were recorded and what the conditions were so its hard to tell what you are seeing along with what others are seeing.
Lets look at the temps you posted and I will compare to mine in the hot line.
My temp is usually around 130 to 140 in 70 degree weather
When the engine is up to operating temp and the trans is fully warmed I see 170-190 from 60 degrees to 110 degrees. This is in lockup, no load, rolling down the road with decent air flow thru the coolers. Your reporting 50-60 cooler than what I and least 5 others with the probes in the hot line typically see, given the conditions I specified.
When the outside temps go into the 80's and 90's, trans goes to 160 to 180 depending on traffic
Under these same conditions and am assuming stop light to stop light type of driving with some idling at the lights, its no unusual to see 220 degrees at the cooler output.Mine is a little cooler because I have a good TC, others have reported seeing 230-240 in the same conditions. I have seen 260 degrees with a heavy trailer and too much traffic that cause speed up\slow down type of driving. In-trans temps will probably never break 200 degrees under these conditions.
Your temps are low because the test ports are not in the main flow of fluid, they will only report the total trans temp or heat soak it achieves. The temps I read take into account whether the TC is locked or unlocked and how much I am loading things to generate heat.
The TC generates over 90% of the heat in the trans, why would NOT want to read it as close as possible to adjust driving? Like I have said before, the hot line gives the ability to be pro-active instead of re-active to trans temps. I have never had to pull over on a grade with any load because my trans temps got to hot, I cna djust gears and lockup on the fly to make sure it never happens.