If I read your post correctly, you are going the long way around in confirming my statement that the placard indicates "Minimum Pressures."
If you run the pressures indicated on the fuel door, in my experience that is almost a GUARANTEE for center treadwear, particularly on the right rear (don't ask me why the right rear will do this more than the left rear because I don't know.) You need to add a few pounds to the rear loaded number.
That's been my experience from almost a million miles of keeping tires on MB's.
Have a great day,