That's strange, cause I have always adjusted my figure as needed. I only work casually, and I always seem to end up with long term contracts (but can never predict them, LOL).. And each time, I just ring and up and advise my wage, and it just reduces my fortnightly payment.

We did exactly what you were talking about last year as DH was on a low wage (training) till Sept, so 3 months and we needed that higher FTB or FTA (whichever it is we get) and CCB, so we kept him at his lower wage till he is training was finished, then I adjusted his figure and they just reduced our payment to collect the over-payment..