Do MPNs really save money?

Just read a an article today from workcompcentral.com regarding the cost efficiency of Medical Provider Networks in Texas and California. There was a study done in Texas showing that MPNs actually cost more; however, California has yet to collect any data. One reason being for an increase cost is implenting Utilzation Review and treatment plans within each MPN. This year California will begin a study to see if MPNs do indeed save money.