; and (B) by inserting after paragraph (2) the following new paragraph: (3) The Secretary concerned may adjust the date of rank of an officer whose name is placed on a reserve active-status promotion list pursuant to subsection (e) or (f) of section 624 of this title. . 504. Flexibility in determining terms of appointment for certain senior officer positions (a) In general Chapter 35 of title 10, United States Code, is amended by inserting after section 601 the following new section: 602. Flexibility in determining terms of appointment for certain senior officer positions The Secretary of Defense may extend or reduce the duration of an appointment made under section 152, 154, 7033, 8033, 8043, 9033, or 9082 of this title by up to six months if the Secretary determines that such an extension or reduction is necessary either in the interests of national defense, or to ensure an appropriate staggering of terms of senior military leadership. . (b) Clerical amendment The table of sections at the beginning of chapter 35 of title 10, United States Code, is amended by inserting after the item relating to section 601 the following new item: 602. Flexibility in determining terms of appointment for certain senior officer positions. . 505. Realignment of Navy spot-promotion quotas Section 605(g)(4)(B) of title 10, United States Code, is amended by striking 325 and inserting 425 . 506. Authority to increase the number of medical and dental officers recommended for promotion to certain grades Section 616(d) of title 10, United States Code, is amended by inserting , except, the Secretary concerned may authorize a greater number of officers so recommended that is less than 100 percent of the number of officers so included, for medical and dental officers recommended for promotion to major or lieutenant commander, if the Secretary concerned determines that such greater number is necessary to maintain or improve medical readiness before the period at the end. 507. Prohibition on appointment or nomination of certain officers who