Samiam4,
You are probably correct that MB would like us to buy new rotors for all our cars($$$). And it is true on the later model cars that MB says you should not have the rotors turned but replaced(More $$$).

The factory 123 manual states-"If the lateral runout of the brake disc is too high...(runout max. 0.12, wear limit 8.3 ) Renew brake disc, if required."

Haynes 123 series manual states- "Any variation over 0.0005-inch may cause pedal pulsation...the rotor can be removed and taken to an automotive machine shop for resurfacing."(page 165)

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Diesel-guy