Technically it isn't a "dipstick" it is considered a "tool" since it is used on various models of Mercedes.
I have found that with the engine cold the fluid level is in the "25 Deg. C" zone and with the engine fully warm the fluid level is in the "80 Deg. C" zone.
From prior posts on this topic, Mercedes recommends checking the level at 80 Deg. C.
1998 Mercedes E320, 200K Miles
2001 Acura 3.2TL, 178K Miles
1992 Chevy Astro, 205K Miles