It had nothing to do with crew licences etc. Just spent a layover with a few involved with the process from JQ, and it was the fact they were going to have to do it all again for another new type to the AOC (787) in just over 12 months, so it made zero sense in spending the money, or time involved to get the 330's onto the JQasia AOC in the meantime. It also means they have alot more flexibility with regards to crewing for another year or so as well.
I believe the costs involved were alot higher than originally expected, and they had a few issues to sort out re the Qf maintenance system in place.