Interesting discussion. But is fuel really that cheap compared to the cost of an engine?
The difference in fuel burn between max power (ROP) and max economy (LOP) is about 20%, or 10 litres an hour in an IO-520. That's $40,000 for a 2,000-hour overhaul at today's fuel prices - the cost of a factory refurbed engine.
Simplistic (yes, unrealistic) figures, of course. But saving even a fraction of that amount puts things into perspective. Fuel is the biggest expense of running an aircraft and the one thing owners/operators have a degree of control over.