If a person covered by paragraph (1) has completed at least six months of satisfactory service in grade, the person was serving in that grade while serving in a position of adjutant general required under
section 314 of title 32 or while serving in a position of assistant adjutant general subordinate to such a position of adjutant general, and the person has failed to complete three years of service in that grade solely because the person’s appointment to such position has been terminated or vacated as described in section 324(b) of such title, the person may be credited with satisfactory service in that grade, notwithstanding the failure of the person to complete three years of service in that grade.