You do realize that in the US oil change intervals are reduced from original Mercedes recomendation of 19,000 miles to 13,000 miles...right?
You do realize that you have higher rates of wear in the first 1,000-3,000 miles of an oils life than later when the oil has approx 19,000+ miles on it...right? The point is to reduce the number of activation cycles of the oil and reduce the engines lifetime (wear metal, ppm/1000 mile/km) wear rates to as low as possible. Engine oil literally at 15,000 miles is protecting your motor as well as when the oil had 5,000 miles in terms of wear metal generation. At 1,000 miles your wear metals being generated are 3-4x's the wear rates at 10,000 miles...
If you doubt this, simply take a sample at 2 miles post oil change. Take another sample at 250, 500, 750, 1000, 1500, 5000, 10,000, 15,000, 20,000...Plot it and you will easily see the activation cycle of the oil additives and the significant drop in wear rates that occur once you get 1,000-3,000 miles on the oil.
Use only approved oils ie MB 229.5 or MB 229.51 and just change it when the computer calls for it.
Stepping off the soap box...
If you doubt me, I have a good friend thats an STLE that I can put you in touch with, he designes these additives and lubicant formulations.
DB