"Any credit identified as an overpayment of income tax instalments will be included on your client’s next income tax assessment as ‘Other amounts refundable’ from the income tax account.
The credit amount can be viewed via the Tax Agent Portal by accessing your client’s income tax and integrated client accounts. The credit will appear as ‘Credit transferred in from another account’ on the income tax account and ‘Credit transferred out to another account’ on the integrated client account.
You can ask for the credit to be retained on your client’s integrated client account by submitting a ‘Transfer request’ via the Tax Agent Portal."
For a copy of the ATO advice, go here