I also did Moominmama's taxes for this financial year. It only took me about 2 hours to do both as I am very organized :) You can find previous years' reports here. Here is a summary of her tax return for this year:
Her salary was up 4% this year. Gross income was down 9% mainly because we lost money on futures instead of winning, I think.
Total deductions rose by 19%, mainly because of increased interest costs and futures losses, which are included as other deductions. As a result, net income fell 38%.
Gross tax applies the tax bracket rates to taxable income. This was more than offset by franking credits. So, she gets the franking credits refunded as cash and has a negative tax rate. She also had to pay tax installments. As a result, she should get a large refund, estimated near $12k.
If we get refunds as big as predicted here they will almost be enough to pay private school fees for both children for 3/4 of the year! One term's fees is one of the monetary units I now think in :)