Reviewing for Accurate Invoice Prices
Comparing prices on supplier invoices to original purchase order prices provides evidence for testing the management assertion of accuracy. Significant discrepancies be- tween expected prices and the prices actually charged may be due to clerical errors, failure to review supporting documents before authorizing payment, or accounts payable personnel exceeding their authority in dealing with price discrepancies.
Traditionally, auditors verify pricing accuracy by comparing invoice prices with the purchase orders on a sample basis only. Of the thousands of invoices processed during the period, perhaps only one or two hundred can be tested manually. ACL allows the auditor to compare the prices charged on every invoice in the file for the period under review. The test will involve the Disbursement Voucher file and the Purchase Order file, which is illustrated with some sample data in Table 10.3.
Testing pricing accuracy involves matching records from the two files using ACL’s Join feature. This can be accomplished in a few simple steps. First, recall from Chapter 9 that both files being joined need to be ordered on a common key. In this example, PO Number is a common secondary key. Reorganizing both files on this field requires open- ing each file separately, invoking ACL’s sort function, specifying the sort field, and des- ignating the file name to receive the sorted output. The results of this process will be two new files ordered in the same sequence.
The next step is to combine the two files to create a third output file. The auditor achieves this with the Join command. Several options are available when joining files. The relevant option in this case is to create an output file that consists only of matched records from the two files. ACL’s Join feature permits the auditor to specify the fields from the two input files that are to be passed to the new output file. Usually, it is neither necessary nor desirable to include all fields from both of the original files. In this exam- ple, the fields needed from the Purchase Order file to verify pricing accuracy are PO Number and PO Amount; from the Disbursement Voucher file the fields are Voucher Number, Amount, Check Number, and Vendor Number. The file structure of the new combined PO/Disbursement file with some sample records is presented in Table 10.4.