(a)(1) Subject to paragraphs (2) and (3), a regular warrant officer who has at least 30 years of active service that could be credited to the officer under section 511 of the Career Compensation Act of 1949, as amended (70 Stat. 114) shall be retired 60 days after the date on which the officer completes that service, except as provided by section 8301 of title 5.

(2) In the case of a regular Army warrant officer, the calculation of years of active service under paragraph (1) shall include only years of active service as a warrant officer.

(3) In the case of a regular Navy warrant officer in the grade of chief warrant officer, W-?5, the officer shall be retired 60 days after the date on which the officer completes 33 years of total active service.

(b) The Secretary concerned may defer, for not more than four months, the retirement under subsection (a) of any warrant officer if, because of unavoidable circumstances, evaluation of his physical condition and determination of his entitlement to retirement or separation for physical disability require hospitalization or medical observation that cannot be completed before the date when he would otherwise be required to retire under this section.

(c) Under such regulations as he may prescribe, the Secretary concerned may defer the retirement under subsection (a) of any warrant officer upon the recommendation of a board of officers and with the consent of the warrant officer, but not later than 60 days after he becomes 62 years of age.