(1) An issuer issuing bonds pursuant to this part shall collect reasonable fees for the services, facilities, and commodities of the undertaking and shall revise the fees from time to time so that the undertaking remains self-supporting.
(2) The fees prescribed must produce revenue at least sufficient to:
(a) pay when due all bonds and interest thereon for which the revenue is pledged, including reserves; and
(b) provide for all expenses of operation and maintenance of the undertaking, including reserves.