I work for a company that manufactures ductwork. Our finished items are essentially the same (i.e. all ductwork), however, based on specs received by the customer, they have different measurements.
We use Autocad for production, which creates a report stating the Job #, the raw materials required for the job and the sqm of finished product. As such, I want to be able to create a BOM based on estimates, but when the production order is processed/costing finalized, I want to be able to change the quantity based on actual quantities used.