Since batch sizes varied from process, the job order accounting approach presented another serious problem. In the aluminum foundry, a job order could be written up for 4000 pieces of the component. If the process were running smoothly, the supervisor could decide to produce enough to release 4500 good pieces to the next stage. Omitted from this count would be items produced in the batch but which had been set aside as scrap or rework. On the other hand, a few hundred pieces could have been added to the batch after they had been reworked from a previous batch.