The interval oil change on my 2005 Mercedes CLK 500 is 12,000 miles per the owners manual and the FSS. It has the big brother engine the M113 to our M112. Which is what nickwe21 posted above.

I also change the oil from above. One time out of curiosity I wanted to know how much oil I was leaving in the engine after vacuum from the top. I removed the drain plug and got an additional tablespoon and a half to drain out.
I also use Needswings oil catch can and sometimes it will have water mixed with the oil and at others it will be just oil. Which is showing me the conditions of the oil changes with the environment the car is driven or stored.

PS I have a lift in my shop.