(a) The impact fees imposed by this division shall be paid in legal tender unless the city council accepts an in-kind contribution of real or personal property for public use which serves the same public purposes as those for which the impact fees are imposed. Credit for such in-kind contribution shall be based upon the fair market value of that property as of the date the city council accepts such offer of dedication. The appraised value of the property shall be verified by at least one competent independent opinion thereof.

(b) All impact fees shall be paid by certified funds at the time of issuance of the certificate of occupancy for such new construction.