The lender, upon endorsement of the note, shall pay the Commissioner a first mortgage insurance premium equal to 0.5 percent of the original face amount of the equity or acquisition loan.

(a) If the date of the first principal payment is more than one year following the date of endorsement, the lender upon each anniversary of such endorsement date, shall pay a premium equal to 0.5 percent of the original face amount of the loan. On the date of the first principal payment, the lender shall pay another premium equal to 0.5 percent of the average outstanding principal obligation of the loan for the following year which shall be adjusted so as to accord with such date and so that the aggregate of said premiums shall equal the sum of:

(1) 0.5 percent of the average outstanding principal obligation of the loan for the year following the date of endorsement; and

(2) 0.5 percent per annum of the average outstanding principal obligation of the loan for the period from the first anniversary of the date of endorsement to one year following the date of the first principal payment.

(b) If the date of the first principal payment is one year or less than one year following the date of endorsement, the lender, upon such first principal payment date, shall pay a second premium equal to 0.5 percent of the average outstanding principal obligation of the loan for the following year which shall be adjusted so as to accord with such date and so that the aggregate of the said two premiums shall equal the sum of:

(1) 0.5 percent per annum of the average outstanding principal obligation of the loan for the period from the date of endorsement to the date of the first principal payment; and

(2) 0.5 percent of the average outstanding principal obligation of the loan for the year following the date of the first payment following the date of the first principal payment.

(c) Until the equity or acquisition loan is paid in full or until receipt by the Commissioner of an application for insurance benefits, or until the contract of insurance is otherwise terminated with the consent of the Commissioner, the lender on each anniversary date of the first principal payment, shall pay an annual insurance premium equal to 0.5 percent of the average outstanding principal obligation of the loan for the year following the date on which such premium becomes payable.

(d) The premiums payable on or after the date of the first principal payment shall be calculated in accordance with the amortizing provisions without taking into account delinquent payments or prepayments.

(e) Premiums shall be payable in cash or in debentures at par plus accrued interest. All premiums are payable in advance and no refund can be made of any portion thereof except as hereinafter provided in subpart E of this part.