At the moment, we're unable to edit the amount on the BASto be lodged in QBO. QBO captures the GST on sales and GST on purchases in your BAS based on the transactions coded with tax codes. If your business is not registered with GST, your purchases will be recorded in the account as a plain expense transaction.
Furthermore, the GST on purchases will be available if the GST is enabled and set up in the GST center. We recommend you contacting your accountant to get more accounting advice on how to record the purchased goods to GST sales in QBO. They're the best ones to provide more information regarding how to track the GST for those purchases.
Please know that you're always welcome to post if you have any other concerns.
Why can't a new GST code be added that addresses this issue? There are a good number of businesses out there that deal in second hand goods. Wouldn't the expense act like a credit note so maybe that is the area that could be adapted for this purpose?
Thanks for your reply, elingbookkeeping.
QuickBooks Online automatically creates default GST rates for you once you've enabled the GST feature. You can use those codes when creating sales and purchase transactions. As of the moment, we don't have an option to create additional GST rates.
Also, we recommend to check with an accountant for an accounting advice and see what options suitable for you. This article from ATO might help you on how to handle second-hand goods purchased from a non GST-registered business.
Feel free to reply on this thread if you have any other questions. Have a nice day!