Prospo Ltd is a major manufacturer of medical diagnostic machines and advanced surgical equipment for the Health Services industry. Prospo uses a complicated accounting information system called ZAP. Detailed below is a description of Prospo's purchasing and payments system.

(i) When the production department requires items to be purchased, a pre-numbered purchase order is created, which is manually entered into the ZAP computer system by the procurement supervisor. The purchase order is then automatically routed to the purchasing department, who then forwards it to the accounts payable clerk when it is ready.

(ii) When the goods are received, the receiving department logs the shipment by entering "order received" in the ZAP computer system which also compiles a date and time-based receiving report of all confirmed deliveries at the end of the day. One copy of the receiving report is filed in the receiving department and the other is forwarded to the accounts payable department.

(iii) The accounts payable clerk matches the purchase order number, confirms the date of goods delivery, based on the receiving report, and then obtains the supplier's invoice, which is normally sent by mail. When the invoice is received, the Accounts payable clerk then enters "Approved" in the ZAP computer system.