Discrimination Against Bikes, and unfair charging

Because they calculate 2 bikes occupy one car lot, car is already $2.16 per hour, so two bikes will also be $2 per hour. But the discriminating thing is bikes are by default $1 hourly charge, not by the minute, i enter only 15min, got deducted $1. Car in front of me got deducted $0.50 as they enter only for 15min too.