A new Billing Due History Report is now available in UBO, specifically under the Billing category of the Report Center.  Similar to the Billing History Report, this report displays all invoice charges generated for the subscriber but displays the charges based on the due date of the invoice rather than the date the item was added to the invoice (yes, these are sometimes different).
In the Billing Due History Report, all invoice charges of the invoice that has a due date within the date range selected will be displayed in the report.

With this new report, you can now see all invoice charges that are set to be due based on the date range you specify.