Sec. 7. As used in this chapter, "money cost index" means any of the following:
(1) The Federal Cost of Funds Index calculated and made available by the Federal Home Loan Mortgage Corporation on or about the twentieth day of each month.
(2) The monthly average of weekly auction rates on United States Treasury bills with a maturity of three (3) months or six (6) months, as published in the Federal Reserve Bulletin and made available by the Federal Reserve Board each month.
(3) The monthly average yield on United States Treasury securities adjusted to a constant maturity of one (1), two (2), three (3), or five (5) years, as published in the Federal Reserve Bulletin and made available by the Federal Reserve Board each month.
(4) Any rate that is designated by the department.