; for purposes of this paragraph only, a determination regarding substantial improvement may exclude the costs of any improvement to a structure or the structure’s associated land area for which the primary purpose is flood mitigation or floodproofing; such improvements may include elevation of the building or utilities, floodproofing, or other site-specific mitigation activities that would otherwise meet the eligibility requirements established by the Administrator under authority of section 1366(c) ( 42 U.S.C. 4104c(c) ). . 5. GAO study and report The Comptroller General of the United States shall conduct a study to determine the feasibility and effects of— (1) eliminating, by January 1, 2027, all subsidies that reduce premiums for coverage under the National Flood Insurance Program of the Federal Emergency Management Agency to amounts that are less than the amount that is actuarially necessary for such Program to operate without a deficit; and (2) prohibiting any subsidy described in paragraph (1) for any property unless mitigation activities to decrease the risk of flood damage to such property have been completed. Not later than the expiration of the 12-month period beginning on the date of the enactment of this Act, the Comptroller General shall submit a report to the Congress that describes the findings of the study pursuant to this section.