a cost reporting period of a sole community hospital or a medicare-dependent, small rural hospital, as the case may be, that begins during a fiscal year before fiscal year 2018. (6) Volume decrease adjustment The term volume decrease adjustment means the adjustment required with respect to a sole community hospital or a medicare-dependent, small rural hospital, as the case may be, under subparagraph (D)(ii) or subparagraph (G)(iii), respectively, of section 1886(d)(5) of the Social Security Act ( 42 U.S.C. 1395ww(d)(5) ).