There shouldn't be any repricing as long as you pick up the same day of the reservation and you return after the same time period (e.g. if you were supposed to pick up at 3 and you pick up early at noon, return it by noon).

I've definitely picked up hours late or early with no issue at airport locations.

Only thing I ran into is after like 4 hours they take away your assigned car (if you reserved a specific class and were preassigned a car) and tell you to go to the gold booth to get a new car. I just picked something from PC and went to the exit booth with no issue.