The Commissioner, after investigation, shall promptly make his finding in writing as to whether or not additional wages are due the employee. If the commissioner finds that additional wages are due, ten percent (10%) of such amount due shall be added as penalty for such wage deficiency. The Commissioner shall mail said findings to the employer and to the employee by certified mail. Payment by the employer and acceptance by the employee of the amount so determined by the Commissioner shall absolve the employer of any further liability to the employee with respect to wages claimed by the employee for the period he was employed by the employer.