Section 114A. Trust companies, savings banks, co-operative banks, savings and loan associations, credit unions, national banking associations, federal savings banks and federal savings and loan associations or federal credit unions or any subsidiary of the foregoing shall not be subject to the provisions of sections ninety-six to one hundred and fourteen, inclusive; provided, that such institutions may not take, receive, reserve or charge interest, expenses and other considerations for making or securing a loan of six thousand dollars or less in excess of those permitted by section one hundred. Any loan of six thousand dollars or less made by any trust company, savings bank, co-operative bank, savings and loan association, credit union, national banking association or federal savings and loan association on which charges for interest, expenses and other considerations exceed those permitted by section one hundred may be declared void by the supreme judicial or superior court in equity upon petition by the person to whom the loan was made, and any such trust company, bank, association or credit union making such loan shall be subject to a fine of not more than five hundred dollars. This section shall not be construed as preventing a rate of charge for interest, expenses and other consideration on one or more portions of a loan in excess of the permitted maximum rate of charge applicable to said portion or portions, provided, that the composite rate of charge on the whole loan produces an amount equal to or less than that which would be produced were said maximum rate of charge applied to said loan. Extension, default or deferment charges shall not be deemed to be interest, expenses and other considerations in determining the maximum rate of charge that may be taken, received, reserved or charged for said loan.