The flight-time-as-compensation is an ugly interpretation. And it has the potential to screw a lot of people who are, in good faith, trying to follow the regulations.
For example, say you take a buddy for a burger run. You rent the plane "wet", so the total cost is easy...it costs you $100.00 for the trip. You each scrupulously pay for your own meals at the end.
How much can your buddy chip in for the plane? Most would say that he can chip in $50, right? Wrong...if he does that, you've received $50+flight time against a $100 bill, so you've received greater (flight time) than your pro-rata share. So then, how much less do you have to accept to balance things out? No clue, the FAA has never quantified what flight time is worth.