(a) The filing date of correspondence submitted under this section is the date of deposit with the USPS if the correspondence: (1) Is addressed as set out in § 2.190 and deposited with the USPS with sufficient postage as first-class mail; and (2) Includes a certificate of mailing for each piece of correspondence that: (i) Attests to the mailing and the address used; (ii) Includes the name of the document and the application serial number or USPTO reference number, if assigned, or registration number