I was just joking with Bot. I thought the uneven increments on the gauge was correlated with the fact that the markings are not sweeping a circle around the indicator.
The MB gauges I've looked at were just a float set in a tube measuring the height of the fluid in the tank. If the shape of the tank is not symmetrical, the float isn't measuring uniform usage as the level drops. The other factor is the orientation of the tank in the car. In the wagons the tanks are under the back section, flat and not very deep. That gauge is more vulnerable to fluctuations as the fluid sloshes around the large flat tank.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13