Properly Accounting for Holdbacks and Progress Payments

Hello,

We have several of our invoices that need holdbacks deducted from the total, and are due 60 days after the end of the project. For anyone else in this circumstance, how are you creating invoices so that the holdback monies are properly tracked (i.e. in AR report)?

Currently, I'm creating a line item for the work and then adding an additional line item with a negative amount to account for the 10% holdback. The issue is that this doesn't show as a receivable and it requires an outside ledger to keep track. One option would be to create a separate Work Order and Invoice for the holdbacks. In some cases we have numerous progress payments so that would mean just as many additional holdback invoices. Ideally I could track them properly inside NS and then create one invoice at the end of the project for the total