OP should have looked at the gas gauge. I got screwed in a major way last nov in kona HI for a few gallons it was $35.00. My fault but change of flights and no gas station open at 5am I got the bill. It was outrageous what was charged for a few gallons but learn by it.
The idea of charging more for fewer days is a SCAM. I dont care about contracts and changes but where does it allow you to charge more for less. i only do this in my business if there is a quantity discount and the change will cost me more to produce less. If they have a paid car sitting around for an extra day they gain by another rental. Stop the BS on upping charges at rental agencies!