Hi,
My CLK 320 W209 has service stamps:
08/10/2004 12,101mls
24/01/2006 21,517mls
29/01/2007 27,584mls
The battery has been disconnected on and off this last year so the ASSYST is wrong.
It's currently on 37,147mls and it's been 27 months since last service.
I can't find anywhere written down...