On acceptance of an application for the surrender of the registration, the Registrar must make a refund of motor tax to the former registered operator calculated in accordance with the following formula:where A is the amount of the refund;B is the number of days remaining in the registration period for the vehicle as at the date of acceptance of the surrender;C is the number of days in the registration period for vehicle;D is the amount of the motor tax paid in respect of the relevant registration period.