The ATO asserted that “We treat a revised activity statement as an application to amend an assessment. If we accept your revised amount in full and the amendment is made within the period of review, the revised statement will be taken to be a notice of amended assessment. The date of effect of the amended assessment is the day we adjust your running balance account.”
The ATO asserts that “it is not what should be done and is not ideal”.
Moreover, businesses do have the right to make revision of Activity Statement, however the contents of the above link need to be noted. Also, depending on the nature of the revision, timing of the revision and the outcome, it does flag the business for further questions/investigation.