A question for those from Australia.?

That's a good try, but not quite right.

The five stars that make up the Southern Cross have points to designate the brightness of each star, so the four brightest stars have seven points, but the smaller star has only five.

The large single star is the Commonwealth Star. Originally this had six points representing each of the six States of Australia. In 1908 a seventh point was added to represent the Australian territories.

http://www.itsanhonour.gov.au/symbols/flag.cfm

From the website: http://www.australianflag.net.au/

The Stars – The Southern Cross

The constellation of the Southern Cross indicates our geographical location in the southern hemisphere. This constellation of stars relates to the various indigenous legends and reminds us of our rich and precious Aboriginal and Torres Strait heritage.

The Commonwealth Star – National Federation

The large seven pointed star is the emblem of Australian Federation. Six points represent the states and the seventh all the federal territories which together constitute the nation, the Commonwealth of Australia.