Hi Beep333,
Thanks for reaching out. This is an ATO reporting requirement; as per their website, 'You must report the year-to-date values of gross salary or wages, allowances or other payments (as relevant), deductions and PAYG withholding for each employee included in that pay event'. Each pay event will update the year-to-date values held with the ATO from the previous report, refer to this article for more information.
-Kass
