If a Worker and an Employer conclude a labor contract, and the Employer has informed the Worker of the rules of employment that provide for reasonable working conditions, the contents of the labor contract are to be based on the working conditions provided by such rules of employment; provided, however, that this does not apply to any portion of the labor contract in which the Worker and the Employer have agreed on working conditions that are different from the contents of the rules of employment, except in cases that fall under Article 12.