You have to watch out though. You are entitled to part b if your income will be zero (or less than about $2000, but don't quote me on that) for the ENTIRE financial year. If you put down zero income, then go back to work halfway though the financial year, you could be overpaid.

It is reconciled at the end of the fin year, so nothing will happen until then.
I used to work at the FAO so if you need any further clarification on any of this, let me know. It is soo hard to get infomation you can understand.