I called centerlink earlier and they said to cancel my PPL claim and start a new one without the family tax included. Then after the financial year I can apply for the family tax when we know a bit more about our circumstances.
They also said that the cut off for ftb payment to change was $94k, so yeah $150k was way off.

So I guess i will just apply for ftb after bubs is born instead. At least that way we will have a better understanding of what DH will be earning.