You can enter same transaction twice times in the “Customer Batch Invoice” without any warning message. It is because the software does not care about the number that you enter in the reference. The software will detect that there are two transactions but are the same data. If you find that there is something wrong in the “Customer Batch Invoice”, you can correct it from the File / Disk Doctor / Correct. If you want to delete the transaction, moreover, you can press “Edit” from the ‘Correct’ mode to change the transaction to zero and save it. Furthermore, you can correct the date from the “Correct” mode also. After you done that, you can see that the date of the transaction is corrected and there is a transaction which show you that the wrong transaction is deleted. You can get more detail from the Help / Online User Guide Chapter 1 – File, page 45 – correcting data file.