just in case this is helpful, "empty weight" or Leergewicht in German law (42 StVZO) seems to mean weight as ready to be driven, with full tank, spare tyre &tc. I am a bit confused here, as at least with current models Mercedes quotes another regulation (92/21/EG) which means tank 90 per cent full plus 68 kg driver and 7 kg luggage weight. Perhaps EU law is now substituted for German law.
I phoned Mercedes in Stuttgart, sent them an email and they said they will check the files. I will let you know.