Each licensed tank wagon operator-importer who is liable for the tax imposed by this act¹ on nonexempt motor fuel imported by a tank wagon as to which tax has not previously been paid to a supplier, shall remit the motor fuel tax for the preceding month's import activities with the monthly report of activities. The remittance of all amounts of tax due shall be paid on the basis of ninety-eight and four-tenths percent (98.4%) for gasoline and ninety-eight and one-tenth percent (98.1%) for diesel fuel.