Section 65O. Any employer to whom an insurer is assigned under the provisions of section sixty-five A shall be entitled to designate any licensed insurance agent or insurance broker to assist him in dealing with said insurer to which he is assigned and with the reinsurance pool described in section sixty-five C. The said agent or broker shall be entitled to a commission fee as set by the commissioner of insurance pursuant to section fifty-three A. An employer may apply directly to the workers’ compensation plan of Massachusetts for coverage under section sixty-five A or sixty-five D. The plan may not charge a service fee, an application fee, or a transaction fee to any employer who makes an application for coverage directly to the plan.