I doubt anyone is going to go from FO jet to Turbo prop. It's hard to tell where a new hire will end up and how long. Assuming it's one big line to the job you want is incorrect as everyone has different needs and desires. It's no longer the case everyone will pack their lives up and move for the next promotion.
From what I saw the latest Aus east coast 73 FO slots went to guys that started in 2013.
What's the go with the 10% VARA thing?
I think it's also important to remember that significant turn over is ocurring and I'm told is going to increase.