Which ONE of the following statements is TRUE? One of our simplifying assumptions is that all units started are successfully completed meaning that we don't have any spoiled units to worry about. One of our simplifying assumption is that 100% of the direct labor is introduced to production at the beginning of the production process. Process costing should be used when each unit or batch has unieue characteristics. The notion of "equivalent units" is very important in job-order costing but is not often used with process costing