You conveniently neglected to mention it was heading down the toilet in the late 1980s until Cathay stepped in, but let's not let a few facts get in the way of a good story.
If staff travel goes strictly on DOJ then why not have KA commands do the same thing. CX F/Os waiting for command at CX should have the option to take an early command at KA. KA pilots won't mind since we're one big airline and once all the CX pilots have accepted or declined their commands at KA in strict DOJ for both airlines, KA command upgrades could continue.
Surely a happy compromise. Staff travel at DOJ for KA commands at DOJ......