Yea but no offence but hasnt this been extensively done already I remember reading about someone who who a two page write up after sending samples away. His point was changing oil in between services is pointless. The oil still works as it should for 15k for example.
It concluded with yes it was unnecessary on a modern car. Yet someone people would still do out of habit. I do it because my car is over 100bhp per ton NA engine. Therefore being less refined and more highly strung it gives me piece of mind.
Your whole basis for an argument is. Regardless of whether you can afford to fly first class for regular business trips. You should always fly economy.