Thanks for the responses - AsiaMiles is certainly very complicated - I am considering transferring points from AmEx but am very confused by the multitude of award types and associated rules. I usually use SQ (with transferred miles) but CX has some destinations which SQ does not (and pretty good availability) - e.g. SYD-YVR via HKG but from reading, even this straightforward itinerary, has at least one "catch" - apparently (if I understand correctly) the web site quotes 145,000 miles for a return trip on CX but if you go to proceed to ticketing this turns out to be 175,000 miles.