Bill Kelting, audit senior from New York City, was assigned to be in charge of the Hogeye Ranch Company audit. Before this engagement the only cows Bill had seen were in pictures. However, Bill knew how to perform an audit. A large sample of sales was traced to sales barn receipts, and expenses were traced to vendor invoices. Cattle were accounted for as purchased, sold, or on hand. All amounts in the financial statements were tied down to Bill's satisfaction. While reviewing the audit working papers on the last day of the audit, the manager inquired as to what happened to the calves. Bill replied that there were no calf transactions because no calves had been purchased during the year. The manager reminded Bill that calves could be acquired on a ranch without being purchased. Bill spent three days past the expected end of the job reviewing birthing records and accounting for the calves. The calves had been exchanged in one transaction for "next spring delivery" of heifers, but the transaction had not been recorded. Substantial changes were required in the financial statements and tax returns, and a large time overrun occurred.

How might this problem have been avoided?