You've got it!
By jove, I think you've got it. Why sign up for something that makes you decide what to do 15 years from now. CX can't even decide what is happenning this summer.
Take the SLS and be a model employee, but don't sign anything. The courts will eventually decide that a company cannot cut your pay if you stay post 55. CX knows that, hence the urgency to have everyone sign COS 08.
It's simple.