10. Notwithstanding anything contained in the first proviso to rule 7, if the invoice in respect of a service, for which point of taxation is determinable under rule 7 has been issued before the 1st day of October, 2014 but payment has not been made as on the said day, the point of taxation shall,–

(a) if payment is made within a period of six months of the date of invoice, be the date on which payment is made;

(b) if payment is not made within a period of six months of the date of invoice, be determined as if rule 7 and this rule do not exist.