According to all the information I have the 13K change interval applies ONLY to the gassers, NOT the diesels. Diesels are 10K service interval using full synthetic oils meeting M-B spec 229.51. Very easy for the dealer to screw this up, especially if they are not used to servicing many diesels- and they won't be until M-B sells a lot more.

I stayed away from the dealer because the parts guy at the dealer I bought the car from gave me a COMPLETELY WRONG part number for the oil filter when I asked. Who knows what they would have done if I wasn't even allowed to watch!