If the seller of an automobile believes that the mileage reading on the odometer is incorrect,the disclosure statement must indicate that the actual mileage is unknown.

According to the Federal Odometer Law, if the seller believes that the mileage reading on the odometer is incorrect or known to be different from the actual mileage, they must indicate that the actual mileage is unknown on the disclosure statement. This is to prevent odometer fraud and ensure that buyers have accurate information about the vehicle's history.