Except as otherwise provided in this section, if any provision of this act conflicts with any local charter provision or any local ordinance, the provisions of this act shall control. The authority to enter into a contract pursuant to this act shall not be affected by any condition or limitation that may be imposed by any local charter provision or local ordinance. However, this act shall not affect any rights of any party under 1947 PA 336, MCL 423.201 to 423.217, except as specifically provided in section 12. In addition, this act does not modify the provisions of 1969 PA 312, MCL 423.231 to 423.247.