$600. for an oil change is about 10 times too much.
There must have been other work done.
When I bought my Benz (in 1991), the dealer had a special promotion giving away free oil changes (oil, filter, quick inspection) as long as I own the car.
What a deal I had.
A quick calculation:
380K on the clock, oil change at each 5K: = 76 free oil change @ $60.00ea:= $4,560.00......in my pocket.
Where's that money gone?
JackD