Converting Work Orders from Legacy into Cloud

Summary: Interested in Converting Work Orders from Legacy system to Cloud

Content (required): We're using the MaintenanceWorkOrderTemplate FBDI to load work orders from a legacy system. The customer is hoping to load completed work orders in addition to open work orders. My question is how to bring in the closed work orders from legacy without hitting cost accounting with charges that have already been billed to the departments owning the assets. I can use a custom work order status to bring in the closed work orders in a released or hold status with the conversion and then update them to closed. But again I'm concerned about charging. The client would