(a) Debentures shall bear interest from the date of issue, payable semiannually on the first day of January and on the first day of July every year at the rate in effect as of the date the commitment was issued, or as of the date the loan was endorsed for insurance, whichever rate is higher. The applicable rates of interest will be published twice each year as a notice in the Federal Register.

(b) For mortgages endorsed for insurance after January 23, 2004, if an insurance claim is paid in cash, the debenture interest rate for purposes of calculating such a claim shall be the monthly average yield, for the month in which the default on the mortgage occurred, on United States Treasury Securities adjusted to a constant maturity of 10 years.