Hey,
I sent off my application today - My current salary is over $56k pa
It depends on how much $ you have left over after your monthly/fortnightly expenses - If you're like me ... not much lol - So for example I only have about $300 disposable income a month after my bills are paid etc so they base it on that - There is no harm in trying and if you have to exaggerate then do it - I know people who have greatly exaggerated their expenses.
I should find out this week if I am approved - there is also a 21.5% fee on top of what ever amount you take out.
Good luck and don't be deterred from applying