With Mercedes, the dipstick is calibrated to read the level of hot oil. Due to thermal expansion, there will be a slight difference between checking the level cold and hot. I check it with the engine at operating temp on level ground after about 10 minutes or so to allow all the oil to return to the sump. The key is to check the level with the egnine at operating temp and allow enought time for the oil to return to the sump.
1999 Dodge Ram 2500 Cummins Diesel
2002 Harley-Davidson Fatboy
Merlin Extralight w/ Campy Record