With respect to a consumer loan which is secured in whole or in part by a lien on real estate under which the aggregate of all sums advanced or contemplated by the parties in good faith to be advanced will not exceed one hundred thousand dollars, the rate of the loan finance charge shall be a fixed nonvariable rate unless the creditor makes the transaction in accordance with any regulation governing alternative mortgages promulgated by the State Board of Financial Institutions or a federal regulatory agency.