Yes I agree there would be a correct "full" volume at service.
We all remember with older cars with physical dipsticks - there can be as much as a litre between Min and Max markings - yet it's perfectly OK to be anywhere between those marks
I can't comment on what the dealers are doing in this regard is right or wrong (obviously they know best and one would hope any subsequent related faults would be covered under warranty as a result of their actions)
But as per the attached photo of my current oil level (4/5ths full) - I don't imagine I'll get a low oil warning unless the engine loses oil and it drops below the Min mark.
