Ann: Appendix 4E, page-11

Reported Profit is Accounting income less Income Tax Expense calculated on Accounting Income. When deciding on the extent of Franking one looks at the balance in the franking account which is a running balance of accumulated tax paid which is calculated on Taxable Income less paid franked dividends.
So the difference is due to timing of recognition of income and expenses between Accounting and Taxable Income.
However the Financial Statement has a note to the effect that under the new AAS17 Accounting Standard there is set out a calculation of Taxable Income which matches Accounting Income but this was not used as it has not been legislated at time of Accounts Preparation.
So in future when it has been legislated the franking of dividends will more align with Reported Accounting Income after tax so future special dividends are morel likely to be fully franked.
Also with more stable Reported Income currently around 80 cents and annual ordinary dividends of 29 cents in 2023 there is scope for more special dividends fully franked in the future.