You should apply these tax tables to your software before making any payments from 13 October 2020 onward.
Since the changes to withholding are made part way through the income year, employers who are unable to immediately import or enter in these changes will have until 16 November 2020 to do so.
However we recommend you do this procedure immediately to ensure your employees benefit sooner from the tax cuts.
If you unable to import these tax tables immediately any ‘over-withholding’ that occurred prior to the you importing the tax tables will be included in the tax assessment of the employee at the end of the income year.