(1) This section applies if—
(a) a CTP premium (the original premium ) has been paid for a CTP policy (the original policy ) for a motor vehicle; and
(b) a change is made in the construction or use of the motor vehicle; and
(c) because of the change, a higher CTP premium (the higher premium ) than the original CTP premium would be payable if a new CTP policy were issued for the motor vehicle.
(2) The owner of the motor vehicle is liable to pay an additional CTP premium, from the day of the change, worked out as follows:
(3) In this section:
P1 means the original premium.
P2 means the higher premium.
N1 means the number of months (including any part of a month) of the whole of the original policy.
N2 means the remaining number of months (including any part of a month) of the original policy.