Hi DavePaton-Live-C, 

Thank you for reaching out on this and welcome to our Community. 

There're a few reasons that might cause what you are experiencing. One of them is amendments from any previous BAS period. I would suggest contacting our support team so we can do a SmartLook (Screenshare) session with you and see how we can assist. Please find our Contact Us page below:

https://help.quickbooks.intuit.com/en_AU/contact

Thank you and please let us know if you require any additional assistance.