I have had a quart of oil used every 1,500 to 2,000 miles on my 190E 2.3-16 since it was new, and it has 206,000 miles on it now. I add a quart when the warning light comes on, then the next time it comes on I change it. As of late, the car is using a little less oil, more like a quart every 2,500 miles to 3,000 miles, depending on where I drive it (mostly city or on the highway, with highway usage getting the lower consumption rate).
Personally I would not worry about the consumption rate you noted. I agree with the P Connor point that when it is filled to the top of the dipstick mark, it may use a little more. On my 240D, the rear seal on the crank leaks and so I park it facing downhill when I can to avoid unnecessary loss of oil. That car will rapidly drop to the half way point on the dipstick and then stay ther for several thousand miles.
So, you usage sounds normal and I would not sweat it. Hope this helps, Jim
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)