Where a mortgage meets the special requirements of § 221.60 or § 221.65, the following procedures are applicable:

The mortgagee shall determine, at least biennially, whether the mortgagor has continued to occupy the property securing the mortgage. If the mortgagee determines that the mortgagor is not occupying the property or that the mortgagor has sold the property subject to the mortgage to a purchaser not qualifying under the provisions of § 221.60(h) or § 221.65(d)(4) (as appropriate) for the continuation of a below market interest rate, interest on such mortgage shall be computed by the mortgagee at the highest rate permissible under the mortgage. The computation at the higher rate shall be effective from the first day of the month following the month in which the right to collect interest at the increased rate first accrued, as determined by the mortgagee.

The mortgagee shall determine the mortgagor's family income, at least biennially, and shall increase the mortgage interest pursuant to the requirements of §§ 221.60(g) and 221.65(d)(5), as appropriate, to comply with the requirements of such sections. The computation at the higher rate shall be effective from the first day of the month following the month in which the mortgagee determines that the mortgagor's family income was increased.

The mortgagee shall notify the Commissioner, on a form prescribed by the Commissioner, within 30 days of making the determination of the right to compute interest at the higher rate, as provided in paragraph (a) of this section, of:

The date on which such right first accrued, and

The outstanding principal balance of the mortgage on the first day of the month following the date on which such right first accrued.

The liability for payment of mortgage insurance premiums shall begin on and be computed from the first day of the month following the date on which the right to compute interest at the higher rate shall have first accrued.