In the case of the purchase or refinancing under this subsection of a multifamily housing project located in an older, declining urban area, the Secretary shall make available an amount not to exceed $30,000,000 of available purchase authority pursuant to section 1720 1 of this title to reduce interest rates on low- and moderate-income rental housing in projects having 100 units or less which otherwise could not support refinancing and moderate rehabilitation without causing excessive rent burdens on current tenants due to rent increases. The Secretary shall prescribe such terms and conditions as he deems necessary to assure that—

(A) the refinancing is used to lower the monthly debt service only to the extent necessary to assure the continued economic viability of the project, taking into account any rent reductions to be implemented by the mortgagor; and

(B) during the mortgage term no rental increases shall be made except those which are necessary to offset actual and reasonable operating expense increases or other necessary expense increases and maintain reasonable profit levels approved by the Secretary.