It isn't about age 65.
As has been stated by much wiser minds than mine on this forum, age 65 is already here. Age discrimination is in the legislation of most of the countries we base in. It is in the legislation of Hong Kong. It's a done deal. CX contracts that specify termination at an age below that of the based country's CAA/FAA/CAD licencing requirements are over-ridden by this legislation.
All CX want to do is to put it into a contract. If they can do this by agreement, then they can get all the A scalers who are on basings in countries where age discrimination law is mature, to accept a lower deal than they are getting at the moment. If a based A scaler does not agree to a new contract, he will continue on A scale when he reaches 55. CX CANNOT make an A scaler drop to B scale on reaching 55. It becomes illegal.
It seems to me they are trying a smoke and mirrors with us to make it seem that they are negotiating with us for agreeing to age 65. When it comes out, read the deal well, and ask lots of questions of those that know (AOA officers mostly, but some fifth column mangers might be a good source too.)
That's my read on it.
