We are finding this out as well on our wagons 617.952. It almost seems as if the car quickly burns off the oil if it is filled to the top line when cold but as the level gets closer to the bottom line on the dipstick then it stays that way longer? Did they make a mistake when they marked the dipstick? It seems to me in one of the two cars the engine seems to run better with less than full oil....faster or more freewheeling like more oil equals more resistance in the crankcase? My 300d non turbo is this way as well. why?