We'll need to take a better look at this, Sammykl_1406.

QuickBooks should calculate the sales tax from the net amount. I suggest reaching out to our technical support for an agent to help you. They have more tools to investigate this further.

Here's how:

1. Open this link: https://help.quickbooks.intuit.com/en_GB/contact.
2. Choose QuickBooks Desktop.
3. Choose Run the business, then click Customers.
4. Click Get Phone Number. 

You can always visit us if you have other concerns. Have a good day!