The diesel FSS is not the same as the gasoline one. The gasoline FSS is more sophisticated. As far as I remember the diesel FSS does not measure the oil resistivity. It only considers time, mileage, starts , etc. I'd have to check my literature, but the diesel system might even be just a straight miles system. I'm away from home and my manuals right now so I can't look that up.

Len
'99 E300TD 61,000 miles