Thank you Riley.
So if I understand correctly, my employer withholds an amount every pay cycle in excess of my compulsory repayments. That excess then gets released to me in the form of a tax refund after lodging my tax return. Why wouldn't my employer withhold only the compulsory repayment?
I still believe that there is a very large discrepancy between the amount withheld and the amount actually paid off my HECS-Help loan. A casual calculation through the tax return site HECS-HELP calculator puts my compulsory repayment for a single year at a substantially higher amount than what has been paid off in total.
How should I go about fixing this?