Notwithstanding anything contained in rule 46 or rule 49 or rule 54, where a registered person is supplying taxable as well as exempted goods or services or both to an unregistered person, he may issue a single 4 invoice-cum-bill of supply" for all such supplies.

Provided that the said single "invoice-cum-bill of supply" shall contain the particulars as specified under rule 46 or rule 54, as the case may be, and rule 49.