Acknowledging that we have an Uninvoiced Debt/Credit Summary report for detailed results which performs well when I call it periodically to catch any items not-yet-invoiced.
However I have some clients with ongoing accounts having Miscellaneous Tasks or similar titles. For these clients, an invoice is generated when the aggregate of small items becomes large enough to justify writing an invoice and having the client remit a payment.
It would be very convenient if the Work & Expenses window could show a total of Uninvoiced Debt/Credits in addition to the Total of all tasks in a project. Then when the Work & Expenses window is opened to add a task, this Uninvoiced Total could serve as a trigger that the project amount had increased to a point worthy of generating an invoice.