MB gauges are more "dynamic" than you would expect for other vehicles. Same for the temp gauge.
When your engine is cold or when you are accelerating, you should see your needle peg to the "3" position. When idling warm or under very low loads, generally under "3" or "2".
"1" or lower may mean that your oil level is a bit low. If that's not the case, you may need to investigate further as to what is causing your low oil pressure condition.
2009 ML350 (84K) - Family vehicle
2001 CLK430 Cabriolet (71K) - Wife's car
2005 BMW 645CI (124K) - My daily driver
2012 Mustang V6 (60K) - Daughter's car