I think its worth remembering that since this thread started that Tamasek no longer has equity in Jetstar Asia and that the new owner Newstar is owned by Qantas and a player with strong Qantas ties.
Hence this move comes after the separation of the Jetstar sister had been resolved by a change in ownership which leaves the Qantas group effectively controlling Jetstar Asia and Jetstar having entirely separate ownership to Tiger.
This makes it easier to grow Jetstar Asia in competition with Tiger and thus make JQ a significant AsiaPacific player, a strategy which was evident in the material released with the annual results. The combined situation also allows for OZ based Jetstar planes to feed passenger to Jetstar Asia in Singapore.