16 CFR 306.6 - Certification.
In each transfer you make to anyone who is not a consumer, you must certify the automotive fuel rating of the automotive fuel consistent with your determination. You can do this in either of two ways:
(a) Include a delivery ticket or other paper with each transfer of automotive fuel. It may be an invoice, bill of lading, bill of sale, terminal ticket, delivery ticket, or any other written proof of transfer. It must contain at least these four items:
(1) Your name;
(3) The date of the transfer;
(b) Give the person a letter or other written statement. This letter must include the date, your name, the other person's name, and the automotive fuel rating of any automotive fuel you will transfer to that person from the date of the letter onwards. Octane rating numbers may be rounded to a whole or half number equal to or less than the number determined by you. This letter of certification will be good until you transfer automotive fuel with a lower automotive fuel rating, except that a letter certifying the fuel rating of biomass-based diesel, biodiesel, a biomass-based diesel blend, a biodiesel blend, or an ethanol flex fuel will be good only until you transfer those fuels with a different automotive fuel rating, whether the rating is higher or lower. When this happens, you must certify the automotive fuel rating of the new automotive fuel either with a delivery ticket or by sending a new letter of certification.
(c) When you transfer automotive fuel to a common carrier, you must certify the automotive fuel rating of the automotive fuel to the common carrier, either by letter or on the delivery ticket or other paper.