§ 106-a. Service charge for receiving, handling and disbursing funds and coupons. The fiscal officer of the political subdivision or of a district therein shall impose upon each contractor such service charge for receiving, handling and disbursing funds and coupons pursuant to section one hundred six of this article as the local governing body of the political subdivision may provide by local law or ordinance. Such service charge shall not exceed a reasonable amount which is generally consistent with charges by a bank or trust company for such a service. This section shall not apply where a political subdivision or district therein has entered into an agreement with a bank or trust company pursuant to section one hundred six of this article.