If you provide additional information then the process will delay more because ATO take more time to check the details whatever you have provided. It takes more than twelve days to confirm and check the information which includes:
Request for advice: It directly affects the tax calculation for specific return like, item in the return is included in the taxable income and finding if private binding rule relate with this return or not.
Details ATO requests: When a client donating to higher than one retirement saving accounts or superannuation fund these will be included in additional information.
Software problems: Included information details cannot be entered on the label which involves label names or field names and value or in a specific field.
Foreign income: Net foreign income can get from a tax treaty country and income tax offset of foreign can be calculated by the ATO.