That's really encouraging that the MB dealer techs have a hard time with this.
I went at it again last night after my commute home. The dipstick was not fully inserted. After bottoming it out, I could get repeated results and she's full at 80°C. Instead of 28" from stem to stern it's now right around 31" which is what others were seeing.
BIG difference in readings with the engine running too. Thanks for the heads up!
Cheers,
Matt