issues final rules implementing the Small Business Runway Extension Act of 2018 ( Public Law 115–324 ), allows the use of a 3-year calculation for a size standard to be applied to a business concern if the use of such 3-year calculation allows such concern to be considered a small business concern under section 3(a)(1) of the Small Business Act ( 15 U.S.C. 632(a)(1) ). (2) 3-year calculation defined In this subsection, the term 3-year calculation means— (A) with respect to a business concern providing services described under clause (ii)(II) of such section, a determination of the size of such concern on the basis of the annual average gross receipts of such concern over a period of 3 years