(b) Loans to members which in the aggregate exceed the amount shown in the schedule below shall be secured by such collateral having a value which is at least equal to any amount exceeding the limits in the following schedule, except that all loans exceeding five thousand dollars not subject to collateral shall be supported by a sworn financial statement:
(1) Five hundred dollars, in credit unions with assets of less than five thousand dollars;
(2) One thousand dollars in credit unions with assets of five thousand dollars and less than twenty-five thousand dollars;
(3) Two thousand dollars in credit unions with assets of twenty-five thousand dollars and less than one hundred thousand dollars;
(4) Five thousand dollars in credit unions with assets of one hundred thousand dollars and less than five hundred thousand dollars;
(5) Seven thousand dollars in credit unions with assets of five hundred thousand dollars and less than one million dollars; and
(6) Ten thousand dollars in credit unions with assets of onemillion dollars or more: Provided, That the commissioner may, upon request and at his or her discretion, approve in writing a higher unsecured loan limit amount for credit unions having assets of one million dollars or more.
(c) A borrower may pay the whole or part of the borrower's loan on any day the credit union is open for business.