TL,
You could be right....but I believe that they had problems recruiting the captains they needed for the initial A-330 and with 9 more A-320's on the way and more A-330's plus the 787 needing to be addressed soon, I believe they are going to have problems getting captains. So my guess is the "flexibility" that they want is the ability to attract captains with higher pay, while at the same time trying to screw it to the entry level cruise f/o's and F/O's.
Time will tell. No matter the answer, if T&C's stay the same, there will eventually be a mass exodus from Jetstar. If I was Virgin and Tiger, I would recruit hard from Jetstar just to decimate their work force. It's hard to compete with your aircraft parked in the corner.