Some oil filters may not retain oil so if you let it sit over night before checking, you could get an incorrect reading. Everybody has their favorite way of doing it but I think the way Mercedes tell you to do it should work. Start engine, stop engine, wait five minutes and check oil

Remember that overfill is bad.

On my 300E, I simply add and even 6 quarts and then drive it for a day. Then I top it up using the Mercedes approach.