With respect to each project insured under this subchapter, the Secretary shall provide that, after the close of each operating year, the investor shall submit to him for approval a financial and operating statement covering such operating year. If any such financial and operating statement shall not have been submitted or, for proper cause, shall not have been approved by the Secretary, payment of any claim submitted by the investor may, at the option of the Secretary, be withheld, in whole or in part, until such statement shall have been submitted and approved.