Every unclassified importer, as defined in paragraph (i) of section one of chapter sixty-four A, shall, on or before the twentieth day of each month file with the commissioner a return stating the number of gallons of fuel imported or caused to be imported into the commonwealth during the preceding calendar month, and such other information as the commissioner may deem necessary, including information relative to the cost of such fuel by type.
Mass. Gen. Laws ch. 62C, § 16