I believe in the oil not the interval.
Normally 6 months with me after the baseline has been set and a LongLife oil higher than MB spec .
A car that's new to me gets serviced max 2 weeks after it's been received as serviced so it's had 3 oil changes in 4K and the oil is now incredibly clean two months on
( the baseline ).
I let the oils detergent and dispersant package gently clean the engine and certainly not a solvent based oil flush.
For the Merc, I use Total Quartz Ineo MC3 5w30 fully synthetic ,229.53 which i s of a higher spec than the MB 229.51. Despite the fact that the dealership assured me that it had been serviced, and the computer gave the next oil change at 330 day's, I changed the oil within 2 week's after getting the car. For the 4 Skoda's in the family "Fleet", 2 x Superb's and 2 x Ocatvia's, I use Castrol Edge Titanium 05w30 LL. ( I seem to remember you saying in an earlier post, Gazwould that the Castrol would be suitable for Mercedes- Benz too as it exceeded MB Spec's ) I have a Total oil change kit on standby, but for the next service after that one, I will try the Castrol...would definitely make the "stock" position easier to manage !!!
The last time I remember oil change's with your kind of frequencies Gazwould, was many years ago. New Morris Minor's ( yes, that far back
) Engine oil would be changed at 300 Miles, Oil drained, engine filled with detergent, run engine for awhile, detergent drained, and engine refilled with "proper " engine oil !!! Next change would be at 1'000 Miles, and there were maximum speed's for each gear during the "Running -in" time.