You have to factor in the obvious.... time of year travelling, weekend travel, gateway point, how many seats, in what class etc.

CX releases award seats as and when it is needed. For some routes like the JFK route, it is rare for F seat to be made available at all, and only a number of J seats too.

But generally, seats are limited .. and CX does release them about 10 months in advance. When they're gone, the 'reserve' goes to their own Marco Polo and Asiamiles members who can waitlist CX awards.