I expected that I might be late in return the car when I rented it because I was travelling with 2 kids. As QEEQ suggested, I checked with Times staff when I rented the car. Times staff at the airport counter told me that JPY880 per hour, JPY1760 for 2 hours. However, when I returned the car at Times store, another Times staff charged me 6000 JPY. They said 2-hour is within 1-6 hour range, so that 6-hour charge applied. No time for me to argue as I was rushing to the airport.