Rates and classes shall be established in writing, complete with a statement of explanation and justification, and the date as of which each such rate or class takes effect.

In the case of rates or classes of general applicability in the Nation as a whole or in any substantial region of the Nation, the Governors shall cause each rate and class decision under this section and the record of the Governors’ proceedings in connection with such decision to be published in the Federal Register at least 30 days before the effective date of any new rates or classes.

In the case of rates or classes not of general applicability in the Nation as a whole or in any substantial region of the Nation, the Governors shall cause each rate and class decision under this section and the record of the proceedings in connection with such decision to be filed with the Postal Regulatory Commission by such date before the effective date of any new rates or classes as the Governors consider appropriate, but in no case less than 15 days.

As part of the regulations required under section 3633, the Postal Regulatory Commission shall establish criteria for determining when a rate or class established under this subchapter is or is not of general applicability in the Nation as a whole or in any substantial region of the Nation.