Ichabod why on earth don't you check with your Prospect rep ??? They negotiate your terms and conditions of employment. If your GM is doing his own thing to reduce costs against the national agreement then Prospect need to know. If he is acting correctly then get Prospect to tell the members what is happening. That is what communication is supposed to be all about.
By all means post the results of your query here but this forum is no substitute for using your union properly.