What are internal control deficiencies in the below sales cycle?

Salescycle

Tankcosellsits residential tanks through a distributor network of several hundred customers. These customers order tanks in batches of at least 10, which is the minimum number of tanks that Tankco will ship. Due to their size and customized nature, commercial tanks are sold in single quantities. The administrative process for invoicing and collection is the same for both divisions.

Orders are submitted through a secure website that is fully integrated with a module of the financial system. Each customer has a unique login and profile that specifies a credit limit and the terms of sale. These terms are populated by the controller, who is the only person with access.

Orders are received by the operations team and shipments are filled from inventory or are scheduled on back order if the inventory has yet to be manufactured. Backlogged orders are typically shipped within a few weeks.

When orders are shipped, the operations people key in the quantity of tanks, and the system instantly and automatically generates an invoice that is sent to the customer electronically. Standard credit terms are net 45 days, although some customers have negotiated early payment discounts, which are tracked in the system.

Remittances from customers are made through electronic funds transfer. The accounting clerk reviews the deposits by viewing an online bank statement daily. A listing of customer receipts is prepared, and entries are made in the financial system to apply remittances against customers' accounts.