03 Caravan with 2.4 Liter losing Transmission fluid

I have done a lot of idling in stop and go traffic this week and the fluid on my Caravan's Transmission is lower than it should so could the stop and go commuting be causing a loss of fluid? Could there be other places the fluid is going? I noticed the outside of the dipstick tube while usually dusty seems to have a light coating of something on it so it is not the usual dusty color. Also, in the Portland Oregon Metro Area the weather has gone from 50-60s and somewhat rainy to 30s-40s and regularly rainy.

How bad is it for the Transmission to be low on fluid and how bad is it if I add a bit too much? I have been adding ATF+4 a bit at the time trying to not overfill it.

My 95 Voyager had a gasket on itsTransmission dipstick which disintegrated after a decade plus of service, but once I wrapped tape around the dipstick to create a snugger fit in the hole (No Overdrive, just a three speed) I stopped having an issue with losing fluid.


UPDATE!
The Transmission Pan Gasket was leaking and that was fixed under warranty. The Transmission Solenoid was going bad and also leaking fluid so I got that repaired which cured the shifting problems and the leak.