Just wanted to point out few things.
Changed oil with Mobil 1 15w50 put is 8.2 quart.
Drove the car so far 1000 miles and checked, no loss of oil, it seems in exact dipstick position.
Also, I changed the oil cap on this car, I noticed the oil leaking from the cap area, and the cap seems loose.
Another problem is, I have noticed on these 98 w210 is the plastic
oil filler neck looses oil and you can see the oil running down.
I will change that next, after changing the cap, so far it looks great.
Check your oil cap, and the filler plastic neck, easy DIY.