Audit of sales revenue

Gustavus plc sells a variety of electrical equipment on a wholesale basis to some 1,500 credit customers. Cash sales are not a feature of the business. Sales orders are received by telephone and are recorded on a pre-numbered order form in two parts. Part 1 is sent to the customer as acknowledgement of the order. Part 2 is used by the manager of the sales office as an action copy. He authorises the order after checking the account balance with the accounts department to ensure that the credit limit is not exceeded. The order is then passed to the warehouse where the goods are picked and sent to despatch. The order form is then passed to the invoice typing section in the sales office, and three-part
invoice sets are typed. Each set is numbered by reference to a number register, and the top
copy is given to the customer with the goods at the collection point. The second copy is an
accounts copy and the third is filed in the customer file in the sales office. There are no other procedures in relation to sales order processing.
Required (a) comment on the system’s weaknesses
(b) Devise a programme of tests which are designed to provide reassurance that sales are
recorded accurately and debts are collectable.