your previous estimate would be increased by 5.4% (i think) which would be how you came to the $78k-ish amount. you can change your estimate if you think it's too high, but given your DH is self employed, i would suggest leaving it a bit higher - you're probably getting the exact same payment as you would be with a $60k estimate, but you're not likely to get overpaid for things like child care benefit
BG...can I ask a Q about the above you said a few pages ago?

It's a bit OT....but I've given them an estimate of 80k for the last two years for DP's earnings, I don't work. I get the base rate of FTB pA + rent assistance + FTB partB. IN reality, because we are contractors, our taxable income is in reality more like under 60k. I purposely over estimated JIC. So would you say that I would still receive the same FTB partA if I gave them our more realistic 60k estimate? See, I was under the impression and hope that when we lodged our tax returns for the last two years (we've had problems and not done it before now) that I would receive quite a large repayment as I overestimated so much...was looking forward to use it to pay off our income tax.
So I'm a bit freaked out to think that I might not be any difference between 60k and 80k...is there a reason for that?