I think it depends on the particular engine. Once I became familiar with the TSB mentioned above, I stopped trying to keep my oil level at the "full" mark. When I do an oil change, I aim for the mid-way mark and do not need to add oil between 5000 mile changes. When I tried to keep it "full" it would use oil until it hit the mid-way mark anyway.
From my reading on this and the Ritter list, this is a very common phenomenon with MB engines. They seem to "like" to maintain a middle-of-the-road oil level. Mine certainly has been doing this since it was a pup.