n the building industry most large contractors keep a percentage of retention on the original quote from a subcontractor. This only gets paid to the subcontractor when the site is completed or anything up to two years after. So you invoice for a certain amount and they pay you the total less 5% retention that you can only claim in about a year. It would be great to have an option to reflect retention only outstanding on your books, apart from actual invoices outstanding per customer. It gets a bit messy when you want to chase retention in the future and their might also still be invoices outstanding due to the contract being over a certain period of time or the customer not paying the outstanding invoice.
The "due" button on the invoice also need to reflect if its actual retention due or the full/part of the invoice.