More like $100-200 bucks extra here in the U.S. But I do agree about the dealer doing their checks and inspections. They'll also update whatever needs updating such as software which is quite often with these new cars.
Where did you come up with your figure? Or is that the "new math" (which is quite old by now)?
9 quarts of Mobil1 0W40
(regular auto parts store, no coupon): $69 (with approx 8% tax)
Fleece oil filter kit (on line, with shipping): $21
Your time (free for comparison purpose)
Most California Bay Area dealers run perpetual specials for $99 to $119 for an oil change on the later model MBs, so that's $10-$30 difference, right in line with BenzyB's estimate.
Since you mentioned "inspections", then for your estimated difference it could be you're comparing the entire "A" service with the dealer's gold-star/red ribbon inspections and a "free" car wash ... but just for an oil change, it's nowhere near that much at most dealers. (Most indies in this area charge $130 and up for a synthetic oil change.)
To the OP, unless you're meticulous about record-keeping, including receipts, the few extra bucks the dealer will charge for an oil change will also result in them entering that maintenance into MB's system, so if there is ever a warranty claim it won't turn into a warranty challenge
. That's entirely up to you. Whether it's worth that to save $20 and perhaps a couple of hours (dropping the car off, shuttle to work, etc. vs. change yourself, take oil for disposal, etc.) once or twice a year, that's also up to you. If I had a new MB I'd probably have a different approach, since mine's out of warranty I definitely take the DIY path.
Take care and enjoy the ride,