Section 3.21 - Order of consideration(a) Accounting Authority applications will be processed on a first-come, first-served basis. When applications are received on the same day, the application with the earliest mailing date, as evidenced by the postmark, will be processed first. Interim accounting authorities seeking permanent certifications through the "grandfathering" process will not compete with other applicants during the first 60 days following the effective date of these rules which is allowed for submission of their applications. After the "grandfathering" process is completed, all other applicants will be processed as in paragraph (a) of this section.(b) At any given time, there will be no more than 25 certified accounting authorities with a minimum of 15 "US" AAICs reserved for use by accounting authorities conducting settlement operations within the United States. The Commission will retain all valid applications received after the maximum number of accounting authorities have been approved and will inform such applicants that should an AAIC become available for reassignment in the future, the Commission will conditionally certify as an accounting authority the oldest of the qualified pending applicants, as determined by the order of receipt. Final certification would be conditional upon filing of an amended application (if necessary). The Commission will inform the applicant of his/her conditional selection in writing to confirm the applicant's continued interest in becoming an accounting authority.