Re: And then billed 3 extra hours?
"The car as delivered used four-star and the upgrade to unleaded (which was lower octane) essentially involved connecting up a jumper wire under the bonnet somewhere."
That's a perfectly legit example of when it should be done; it's a configuration change to meet different conditions of use, and unleaded wasn't an upgrade; if anything mpg goes down.
Better than having to spend time in a garage while either an ECU was remapped or the ignition advance and retard was replaced.
My boiler has something similar to switch from methane to propane, though there is a jet has to changed as well.