I appreciate you for sharing the details with me. I’m here to help and get this sorted out.
By the way, good job on customizing your invoice format. To use your personalised format, you’ll want to ensure you’ve selected as the default template of your invoice. This way, the Discount and round off option will reflect on your invoice.
Let me guide you how to do it in your QuickBooks Online (QBO) account:
Go the + New menu.
Click Custmise at the bottom of the invoice.
Select the invoice template you’ve created.
Enter the needed information and click Save and send.