While it isn't even worth arguing over a couple bucks I have noticed this on two of my previous rentals in Denver.

So generally as a CHM the gas rate for rental return is about 18-20 cents per mile (actual cost). However, er I have been charged the higher $13.99 rate (+13.25% tax) instead of the actual cost for gas on a 31 and 61 mile rental. In theory (can't remember the exact rates) I should have been only charged about $6 and $12 respectfully. Why is this other fuel service fee overriding the normal fuel rate for CHM?

In addition, as a CHM when I am charged my fuel rate it is normally an untaxable item.