Looks like there is what I call small variation on how to check and fill the tranny. The differences are checking it at neutral or park and checking at between 30-50 deg C and 140 F (50 deg C= 122 deg F).

Bottom line here.

Does anyone who used these procedures ever had a problem associated with under or over fill tranny.

Like I said before the only thing I worry about is not know if at a certain temperature (say at 140 F) a valve open (say to the oil cooler) which will significantly change the fluid level at the pan.

***update****

Check my research, but it look like the valve (Thermostat) that controls the transmission oil cooler is on the radiator side (attached article). So that stands to reason the fluid is always circulating on the oil side of the tyranny, so that should not change the oil level in the pan.

BMW X5 Transmission Cooler and Thermostat Replacement (E53 2000 - 2006) | Pelican Parts DIY Maintenance Article