(a) Except as otherwise provided in §§ 97.201 through 97.204 , §§ 97.206 through 97.208 , and subparts BBB and CCC and subparts FFF through HHH of this part, a CAIR SO2 opt-in unit shall be treated as a CAIR SO2 unit for purposes of applying such sections and subparts of this part.(b) Solely for purposes of applying, as provided in this subpart, the requirements of subpart HHH of this part to a unit for which a CAIR opt-in permit application is submitted and not withdrawn and a CAIR opt-in permit is not yet issued or denied under this subpart, such unit shall be treated as a CAIR SO2 unit before issuance of a CAIR opt-in permit for such unit.