(a) Notice of Disagreement. In simultaneously contested claims, the Notice of Disagreement from the person adversely affected must be filed within 60 days from the date of mailing of the notification of the determination to him or her; otherwise, that determination will become final. The date of mailing of the letter of notification will be presumed to be the same as the date of that letter for purposes of determining whether a Notice of Disagreement has been timely filed.

(b) Substantive Appeal. In the case of simultaneously contested claims, a Substantive Appeal must be filed within 30 days from the date of mailing of the Statement of the Case. The date of mailing of the Statement of the Case will be presumed to be the same as the date of the Statement of the Case for purposes of determining whether an appeal has been timely filed.

(c) Supplemental Statement of the Case. Where a Supplemental Statement of the Case is furnished by the agency of original jurisdiction in a simultaneously contested claim, a period of 30 days from the date of mailing of the Supplemental Statement of the Case will be allowed for response, but the receipt of a Supplemental Statement of the Case will not extend the time allowed for filing a Substantive Appeal as set forth in paragraph (b) of this section. The date of mailing of the Supplemental Statement of the Case will be presumed to be the same as the date of the Supplemental Statement of the Case for purposes of determining whether a response has been timely filed. Provided a Substantive Appeal has been timely filed in accordance with paragraph (b) of this section, the response to a Supplemental Statement of the Case is optional and is not required for the perfection of an appeal.