H.Amdt.718 - Amendment phases out subsidized premiums for severe repetitive loss properties, substantially damaged or improved properties and policy holders who voluntarily allow flood coverage to lapse; clarifies application of actuarial rate phase-in for pre-FIRM properties sold after enactment; provides preferred rate premium for properties participating in NFIP during newly established, 5-year delay in mandatory flood insurance purchase requirement; expands availability of installment premium payment program to all policyholders; clarifies that the FEMA Director may work directly with property owners to make mitigation grants for certain repetitive loss properties where States or communities are either unable or unwilling to address repetitive loss issues with a property owner; allows commercial properties with swimming pools located below the base flood level to enclose those pools with breakaway walls outside of hurricane season; requires FEMA to review mapping of surrounding properties follo