I waited a few thousand miles to follow up... just to be sure.
The sender was replaced with VDO unit. The car is still full of Mobil 1 0w40. The oil pressure is just fine at all temperatures now. The lowest it dips is just above 2 bar and that is at a stoplight right after interstate speeds. That is exactly how it used to read.

Thanks to all for your help and feedback!

__________________
Tim Benner

00 ML320 170K
95 E320 wgn 160K