The reasons are well understood by me and I don't take shortcuts on safety related servicing.
My point is that the dealer takes no account of what else could be done when the car is called in for service. 'Computer says no!' There was not even a suggestion that an oil/ filter change could be done a few miles early so as to avoid a second day without the car.
Frankly it's poor service typical of the arrogance with which many prestige car dealers seem to treat their customers. They are more interested in your money than providing a good service which would be much more likely to guarantee your continued custom.