All interested persons will have the opportunity to consult with and obtain information from the PMA, to examine backup data, and to make suggestions for modification of the Proposed Rates for a period ending (a) 90 days in the case of major rate adjustments, or 30 days in the case of minor rate adjustments, after the Notice of Proposed Rates is published in the Federal Register, except that such periods may be shortened for good cause shown; (b) 15 days after any answer which may be provided pursuant to §903.15(b) hereof; (c) 15 days after the close of the last public forum; or (d) such other time as the Administrator may designate; whichever is later. At anytime during this period, interested persons may submit written comments to the PMA regarding the Proposed Rates. The Administrator may also provide additional time for the submission of written rebuttal comments. All written comments shall be available at a designated location for inspection, and copies also will be furnished on request for which the Administrator may assess a fee. Prior to the action described in §903.21, the Administrator may, by appropriate announcement postpone any procedural date or make other procedural changes for good cause shown at the request of any party or on the Administrator's own motion. The Administrator shall maintain, and distribute on request, a list of interested persons.