in a subsequent year, shall be equal, subject to subparagraph (E)—
(I)#
to the average acquisition cost for the drug for that year (which, at the option of the Secretary, may vary by hospital group (as defined by the Secretary based on volume of covered OPD services or other relevant characteristics)), as determined by the Secretary taking into account the hospital acquisition cost survey data under subparagraph (D); or
(II)#
if hospital acquisition cost data are not available, the average price for the drug in the year established under section 1395u( o ) of this title, section 1395w–3a of this title , or section 1395w–3b of this title , as the case may be, as calculated and adjusted by the Secretary as necessary for purposes of this paragraph.