Is it possible for a tranny to run too cool?

I have a 01 supercrew, 2WD, 5.4, towing package - based on the ScanguageII, which I understand picks up the temp from the valve body (not the hottest point in the system) - the hottest I've see it (summer time traffic jam) was 165* - highway 125-130. Currently, winter temps barely reach 120* at highway speeds a little cooler.

Is this a problem? Cool is better than hot - but, it needs top get hot enough to burn off moisture.

My concern is based in part on what I feel is an increase in slippage between the 2nd to 3rd shift, and some odd feeling upshifts. The tranny was rebuilt 6K miles ago (at 82K miles). The rebuild is under warranty - but, the OD light isn't flashing, and someone that doesn't drive it daily may think it's shifting fine. Better yet - it may not act-up on the 10 minute test drive.

I've considered have the fluid and filter changed to see if that makes a difference.

Thoughts?
Thanks in advance,
Brad