Section 6. A schedule of fees and charges to be assessed for the cashing of checks, drafts or money orders shall be filed by each licensee with the commissioner annually on or before a date to be set by the commissioner and, together with any revisions thereto, shall be conspicuously posted in each place of business and mobile unit of a licensee. An amendment to such schedule occurring between filing dates or a change in the hours of operation, as specified in the application for license filed pursuant to section three, shall be filed, in writing, with the commissioner forthwith.