Section 208. Agreements and Regulations as to Methods of Adding the Tax.--(a) To provide uniform methods of adding the average equivalent of the tax imposed by this act to the sale price in each sale subject to the tax, appropriate rules and regulations may be adopted, subject to the approval of the department, by competing taxpayers or associations of taxpayers. Such rules and regulations shall provide that the tax shall in each instance be computed and collected on the basis of the total transaction, without regard to the value or price of the separate items making up the total amount of a single sales transaction. Such rules and regulations shall not, if complying with the foregoing provisions and not involving price-fixing, be deemed illegal as in restraint of trade or commerce or otherwise. The department may cooperate in formulating such rules and regulations and shall approve any such rules and regulations which it finds to be in compliance with this act.
(b) In the event appropriate rules and regulations governing any class of business are not submitted to the department for approval within such time as the department prescribes, which shall be not earlier than thirty days after the effective date of this act, the department shall, as soon as reasonably possible, formulate and promulgate rules and regulations to effectuate the purpose of this section.