Just wait if you make a change after the car is picked up.

$10.00 change fee
$10.00 fee for being late (29 min of grace) plus almost a full day fee for the 1st hour for being late.

While a agree the add ons are from taxing authorities, and must be listed that way, and airlines do the came. It is the concession recoup fee, just add that into the base fee, just like all of the other concessions do at the airport when setting their prices