Your MB oil change (A service) cost data must be a bit dated.
$250+...here.
For folks even remotely mechanically adapted, a MB oil change is very simple.
Buy a 12V dipstick oil pump on E-Bay for $17, and pump the old oil out.
The MB filter is a top mounted cartridge type, so just screw the cap off and drop in a new MANN cartridge ($9.00 - E-Bay).
Add oil (7qts.- Walmart - Mobil 1 = $38)
Total cost of oil and filter = $47
Time ..... 15 minutes.
I am rapidly closing in on 80.
I believe I will still be able to change my MB oil if/when I might hit 90.
Even though it is ridiculously (expensive) complex, I do think my MB E350 is one he11 of a car!
I bought my MB used.......oops... I meant "pre-owned".....what a crock!