I appreciate you for taking the time in reviewing this thread, @JRG5.
I can see how beneficial it is to your business to adjust the terms of your invoice after the end of the month terms.
While this option isn't available in QuickBooks Online (QBO), I recommend utilizing a third-party app that has the feature you need. Simply go to the Apps menu inside your QBO and look for an app from there.
I'd also suggest sending your feedback to our Development team. Your opinion matters to us as this helps us improve QBO to suit your business needs.
Additionally, in case you want to learn how to modify your sales form in QBO, feel free to check out this article for reference: Customise invoices, quotes, and sales receipts in QuickBooks Online.
I'm all ears if you need more help managing your invoices or QBO. It's always my pleasure to help you. Have a good one!
