32.3. Where a supply of a service is made to a person for consideration that includes a payment that is attributable to a period (in this section referred to as the “billing period”) that is the whole or a part of the period during which the service is or is to be rendered under the agreement for the supply,(1) the supplier is deemed to have made, and the person is deemed to have received, a separate supply of the service for the billing period;
(2) the supply of the service for the billing period is deemed to be made on the earliest of(a) the first day of the billing period,
(b) the day on which the payment that is attributable to the billing period becomes due, and
(c) the day on which the payment that is attributable to the billing period is made; and
(3) the payment that is attributable to the billing period is deemed to be consideration payable in respect of the supply of the service for the billing period.