And many times I'm draining the ATF at the same time and it needs to be cold on my "no dip stick" cars. Therefore drain the hot oil and key the ATF cool down overnight.
Have you actually seen a meaningful change in the measurement ? I've tried this, saw nothing substantial enough to "waste" add'l time.
In several of my cars that don't have the ATF dip stick, I had them filled to the correct amount by using the Scan Gauge, temp, etc. Since I know these AT's have been filled correctly, I don't wanna have to do the Scan Guage deal over and over. So, I let them drain cold (ambient temp) and then precisely measure what comes out and refill with the exact same amount.
Temp makes a difference when measuring my ATF's (T-IV and WS)
So I am draining hot oil, wait overnight, drain the cold ATF, measure amount of ATF and replace with what was removed. If I remove the ATF hot and replace with the exact same amount, I will be overfilling my AT's.