47.1. For the purpose of computing the exigible interest, where an operator pays to the Minister all or part of the amount the operator is required to pay following a notice of assessment, the date of payment is deemed to be the date of mailing of the notice of assessment if the payment is made before the twenty-first day of the month following the month in which the notice of assessment was mailed.
The same rule applies where the payment is made by remittance to the Minister, before the day referred to in the first paragraph, of a negotiable instrument falling due before that day.