The Secretary shall establish standards to promote the maximum use of private financing. If a portion of a rehabilitation project is to be financed by a private lending institution, the Department shall require that the sponsor use all the private financing that the rehabilitation project can support without impairing: the rehabilitation project; or affordable housing for families of limited income, if the rehabilitation project is residential. As long as the State complies with all applicable federal treasury regulations governing borrowing money by the State, a Program loan shall be at an interest rate that at least covers: the administrative and other expenses of the Program; and reasonably expected losses from defaults on Program loans.