Because of the CoS for the flight crew CX would not dare mess with the medical as they know that they would be in the high court post haste.
Same goes for the A scale (pre 93) and B scale (93-97) ground expats.
Post 97 ground expats, cabin crew and all local ground staff are on 'RIGHTchoice' so they get whatever the company considers as RIGHT at the time in question.
Moral of the story: Cathay will treat its staff just as well as they have to to keep our of court (most of the time).
BTW the flight crew will get all of the upside of the new scheme with none of the downside.
I'm not surprised that the AOA is not saying anything (except maybe 'I'm all right Jack')