Jetairways
My personal view is that it because they can put you to work right away and also they don't have to schedule you for a sim for another 3 months.
My understanding is that you are flying based on your JAA/FAA credentials including your PC. Once they expire then you have to get a PC. It gives them some breathing room considering how busy their training schedule is right now. Thats my take on it. I could be totally off on this one.