billing unit
(6) Use of volume-weighted average sales prices in calculation of average sales price (A) In general For all drug products included within the same multiple source drug billing and payment code, the amount specified in this paragraph is the volume-weighted average of the average sales prices reported under section 1396r–8(b)(3)(A)(iii) of this title or subsection (f)(2), as applicable, determined by— (i) computing the sum of the products (for each National Drug Code assigned to such drug products) of— (I) the manufacturer’s average sales price (as defined in subsection (c)), determined by the Secretary without dividing such price by the total number of billing units for the National Drug Code for the billing and payment code; and (II) the total number of units specified under paragraph (2) sold; and (ii) dividing the sum determined under clause (i) by the sum of the products (for each National Drug Code assigned to such drug products) of— (I) the total number of units specified under paragraph (2) sold; and (II) the total number of billing units for the National Drug Code for the billing and payment code. (B) Billing unit defined For purposes of this subsection, the term “billing unit” means the identifiable quantity associated with a billing and payment code, as established by the Secretary.