Sonny -
Flights ex-AVV are bursting at the seams. There is very few seats available. If all you can find are the dearer fares it means the flights are chockers.
Same when people used to compare DJ and QF and say DJ was dearer. Yeh it was but all its cheap seats were gone. So QF was dumping cheap seats or the cheap seats they did have weren't taken (as they had more capacity). Either way. For JQ to be more expensive it actually means they are doing well!
JQ have 3 flights to SYD and 2 to BNE. How many do the others have? (I wouldn't call AVV-SYD competing with MEL-SYD.) You need to take into account load factors and capacity etc. (Apples with apples etc.)