We have a custom sales transaction with a workflow that allows us to "transform" the items to an invoice. That said, there isnt' anything stopping the same item(s) from being continuously invoiced. For instance, when using the native Sales Order, you would use the "Bill Remaining" button to invoice the items, and NetSuite would prevent you from being able to re-invoice the same item(s). Any ideas for how we could re-create this functionality with a custom sales transactions/workflow?

Interested in a solution to this as well