(a) Filing with the Commission. The filing of any written document required by these rules or any applicable statute, rule, regulation or order of the Commission, or by direction of the presiding officer shall be made by filing with the Office of the Secretary, Postal Rate Commission, Washington, DC 20268-0001, during normal business hours on a date no later than that specified for such filing. Documents received after the close of normal business hours or on a Saturday, Sunday, or holiday, shall be deemed to be filed on the next regular business day.

(b) Acceptance for filing. Only such documents as conform to the requirements of this part and any other applicable rule, regulation or order of the Commission shall be accepted for filing. Unacceptable filings will be rejected by the Secretary and will not be included in the file in the proceeding involved. The Secretary shall notify the sender of any unacceptable document and the presiding officer in the proceeding in which such document was tendered that such document was rejected. Acceptance for filing shall not waive any failure to comply with the rules, and such failure may be cause for subsequently striking all or any part of any document.