Thanks for posting in the Community, @kevin179.

Once the late fee feature is on, QuickBooks calculate the late fees and automatically applies them to overdue invoices as a line item. That's why the charge posts back to the original invoice. 

If you'd want to apply the charges to a specific date, you can manually delete the line item for late fees. Then, create an invoice for it and add the late fees.

To delete the late fee from the original invoice, here's how:

1. In the left menu, click Sales.
2. Select the Invoices tab.
3. Locate and open the invoices with late fees.
4. Click the trash can icon In the Late fee line item.
5. Select Save and close.

Once done, you can now create an invoice for the late fees.

1. In the left menu, click the + New button.
2. Select Invoice.
3. Select the customer from the drop-down.
4. In the Product/Service column, select Late fee.
5. Enter the amount and necessary information, then click Save and close or Save and send.

To learn more about late fees, visit this article: Apply late fees to overdue invoices automatically in QuickBooks Online.

In case you need to send statements to your customers with the late fees and other paid balances, here's an article to help you with the steps: Create and send customer statements in QuickBooks Online. 

Don’t hesitate to leave a comment below if you have other QuickBooks concerns or questions about handling late fees. I’ll get back to lend a helping hand.