Is it not just a case of subtracting the cost of an hour's very well-managed fuel- burn?
It is alleged that "wet" renters fly "balls to the wall" 'cos it aint their fuel-bill, whereas a "dry" renter will pay for mismanagement.
setting a dry rate would be a bit of a stick and carrot exercise, IMO......but I'm not a heli pilot, so read into it what you will.
