They don't have to backdate from the old EBA, or provide backpay. Not in the law.
Since we voted down the last one (where backpay WAS provided), there's no obligation for Jetstar (or indeed, any company) to give backpay.
The $800 is an incentive for those who wish to vote 'Yes'. Not too bad a deal if you're new, which for the last 200 or so recruits, is not a bad thing!
Most of the feedback I'm getting is good. At least there's a BOC allowance now.