Transmission fluid increase amount after cooler install

Just a question about the factory Toyota thermostat and after market cooler I installed awhile ago.

When shutting off a hot engine and the transmission fluid temp is still above the temp to open the thermostat, does fluid from the cooler and lines drain back into the pan since the thermostat is in the open position?

I ask because I’ve had more fluid at the first drain and fill than the pan recommended 2.2qts. I’ve also had less than 2.2qts at the first drain.

 

You should have the thermostat pinned open when checking/draining the fluid anyways.

 

Done a few drain & fills, and each one was 3.5 to 4 quarts.