It started with W211, but it now extends into other models (including older models). It applies to M112, M113, M166, M271, M275, M104 (although I wouldn't on this engine) and a few others. The ML's, some cross country vehicles and I think all diesels don't get the longer drain interval.
Service sheets for W168, W202, W203, W208, W209, W210, W215, W220 have all been progressively updated accordingly.

__________________
Alex.

MB Tech
Sydney, Australia
Volvo 122S
W201 190D 2.5 manual
W202 C240
W203 C32