Flights from Melbourne, Sydney & Gold Coast to Kuala Lumpur are $10 cheaper than this deal in January. These prices are available for flights departing and returning in March. For my test, I used depart March 5, return March 12.
EDIT: Spent some time testing this thoroughly. To get these prices, you can depart 1st to 16th March, and return any time up to 16th April, as long as you stay away at least 4 days. Cheers.
On a side note, any particular dates we should know about? You have only linked to a booking page, rather than an actual deal. When you go to the AirAsia homepage, all you see is advertisements for their "biggest sale ever", which this could surely not be as you have shown above.