For the purposes of these rules, unless otherwise stated, "point of taxation" shall be determined in the following manner, namely:-

(a) a provision of service shall be treated as having taken place at the time when service is provided or to be provided; and

(b) if, before the time specified in clause (a), the person providing the service issues an invoice or receives a payment, the service shall, to the extent covered by the invoice or the payment made thereof, be deemed to have been provided at the time the invoice was issued or the payment was received, as the case may be, whichever is earlier.

Explanation.- For the purposes of this rule, wherever any advance, by whatever name known, is received by the service provider towards the provision of taxable service, the point of taxation shall be the date of receipt of each such advance.

Explanation 2.- For the purposes of this rule, in respect of services taxable under section 66A of the Act, the point of taxation under clause (b) shall be the date on which the invoice is received, or the payment is made, as the case may be, whichever is earlier.