(a) In negotiating terms for a supplemental rebate amount, the commission shall consider:
(1) rebates calculated under the Medicaid rebate program in accordance with 42 U.S.C. Section 1396r-8;
(2) any other available information on prescription drug prices or rebates; and
(3) other program benefits as specified in Section 549.0106(b).
(b) In negotiating terms for a supplemental rebate, the commission shall use the average manufacturer price as defined in 42 U.S.C. Section 1396r-8(k)(1) as the cost basis for the product.