First, I'd remove your membership number from your post.

Your frustration isn't uncommon. But...that's how most reward programs work. If you want the flexibility of being able to book and confirm immediately, you pay cash. If you are willing/able to give up some flexibility in return for not having to shell out hard cash, miles can be spectacular value. If you read around here, you'll find a lot of info on when CX tends to release reward seats that might help you manage your expectations. When are you hoping to travel?

FWIW, I haven't found AsiaMiles to be much better or worse than any other program in this regard -- and that includes redeeming mileage tickets on what are supposed to be premium routes like HKG-JFK. But like all programs, it does reward a certain amount of research on how to get the most benefit out of the miles.