Thank you both. That makes sense the way you explained it.

We have a Medicare levy of 2%. This is a tax. Our Medicare scheme is broader than yours. We have a superannuation contribution of 12%. This is not a tax, it is 12% of your gross income compulsorily paid by your employer into a superannuation fund of your choice. You can't withdraw from it until you retire. You can optionally pay more in at any time. The account itself is in your name and under your control.