Payments under a financing agreement for a project must be sufficient at all times to pay any maintenance and operation costs for the project, unless the maintenance and operation costs are otherwise provided for under the financing agreement, the principal of and interest on any evidence of indebtedness, and a proportion of the administrative expenses of the commission as provided for by each financing agreement, and the reserves as may be provided in the resolutions authorizing the issuance of evidences of indebtedness.