Hello PASC,
Thank you for connecting to the QuickBooks Community! For this situation, you would need to manually add this interest as a line item on the older invoices. Regarding getting the compound interest charge, that would also need to be calculated separately. Please use the steps link below to assist with creating a line item.
- Go to Lists, then select Item List (for Windows) or Items (for Mac).
- Select Item then New (for Windows) or plus + (for Mac), then select New Item.
- Select the type of item you want to create.
- Fill out the item fields.
- Use Custom Fields to add your own customized fields.
- Select Save.
Let me know if you have additional questions. I'm more than happy to help. See you soon.
