Kru,
I would never attempt to answer that question as it's over my head. Were I in your shoes, my first call would be to your council's R&I guy. I am confident that if he can't answer your question, he will be able to direct you to someone who will. Just another benefit that union membership gets all of us. Contractual gains and nuance often don't mean a thing and are overlooked until you're the recipient. (For you dimbulbs, it's not the answered call, it's the language on the page that prompts the call).
Sorry to hear that you've been rolled into the hangar. Unless of course...well, let's leave it at that. Hurry back? Or, don't.
Enjoy your retirement.