Don't understand either of these posts. fluffydot, do you already hold a reservation and are asking about seat assignment? If so, calling up as an MPO GO should yield seat assignments. Inability to book seats on the web is a known issue after the system "upgrade" a few months ago.
hkskyline, if you're asking about availability for purchase/redemption, surely you're aware that the seat map is not a reliable indicator of availability since so many pax may be confirmed/ticketed but not yet have selected seats. The same goes for fluffydot if I misunderstood and you're still trying to make a booking.
In all cases, a call to MPO/AsiaMiles is in order.