I hope hes checking on running engine - regardless of temperature.

Check the level with car parked on flat surface, and when its dead cold - e.g. first start in morning the fluid should be about 5mm below the lowest mark on dipstick, if its not at that mark then you are overfilled. Which you can verify by driving it for 10 minutes to warm up the ATF and check it, it will be above the top marks.

Another factor that is mostly ignored by most is the flow of ATF from the ATF cooler in the radiator, it maybe plugged with clutch debris (only seen a handful on mercedes though) - there is a product sold to clean the cooler too - a semi clogged cooler can cause lethargic shifts sometimes and also cause wild fluctuations in the fluid level. (I experienced a partial clogged cooler case in an old chrysler van - it was a headache and a half anyway)

__________________
2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)