Question: Charlotte interviewed the regional sales manager, Wilbur Boar, who explained that the increase in sales was due to a price increase enacted by the company during the year. How would the Charlotte test the regional sales managers explanation? Perform additional inquires with sales personnel. Obtain copies of all price lists in use during the year and vouch the prices to sales invoices. Send confirmations asking customer about unit price paid for product. Trace vendor invoices to payments made after year-end.