Read the following and identify a weakness within the internal controls. How would you fix that weakness?

Accounting. Billing prices all sales orders received, which is done approximately 5 days after the order ships. To spread the work effort throughout the month, customers are placed in one of six 30-day billing cycles. Monthly statements, prepared by Billing, are sent to customers during the cycle billing period. Outstanding carry forward balances reported by Accounts Receivable and credit memos prepared by the credit manager are included on the monthly statement. Billing also prepares electronic sales and credit memos for each cycle. Electronic copies of invoices and credit memos are forwarded to Accounts Receivable for entry into the accounts receivable master file by customer account. An aging report is prepared at the end of each month and forwarded to the credit manager. The general accounting office staff access the accounts receivable master file that reflects total charges and credits processed through the accounts receivable system for each cycle. General accounting runs a query to compare this information to the electronic sales and credit memo and posts the changes to the general ledger master file.