also allow the supplier to sell the products in the contract to reduce the quantity. The supplier also has to talk and inform the buyer about the quantities of goods kept in order that the buyer could know the status of the stock. Before the buyer issuing the purchase order to the supplier, the buyer must ask the supplier first about stock availability to avoid the problem from no stock availability. Blanket orders or call-off orders may also be used for ordering services, for example for maintenance and repair services. In these cases, the benefits associated with stock-holding do not arise but the call-off order may allow emergency repairs or on-call maintenance to be arranged easily at guaranteed rates. Difficulties The most difficult part of having a contract is determining the forecast quantity arranged by the user of the product. As the forecast quantity can be difficult to get, the supplier must be aware of the quantity to keep in stock. An easy way to do this is to discuss with the buyer what quantity to keep in stock. For example, they might keep only 20% in stock in the first 6 months, so that the supplier and the buyer are able to review the quantity and adjust it appropriately. This reduces the stock burden of the supplier during the contract period and might help the buyer at the end of the contract if the stock does not move as quickly as anticipated. The contract might be extended year after year, but it can be adjusted each time as more relevant forecasting history will predicate the need to decrease or increase stock requirements. Alternatively, some companies may utilize forecasted information via a material requirements planning system to determine appropriate stock quantities throughout the product's life cycle. Federal Acquisition Regulation The United States' Federal Acquisition Regulation uses the term "blanket purchase agreements" or BPAs. According to the U.S. General Services Administration, BPAs: Provide opportunities to negotiate improved discounts Satisfy recurring requirements Reduce administrative costs by eliminating repetitive acquisition efforts Permit ordering activities to leverage buying power through volume purchasing Enable ordering activities streamlined ordering procedures Permit ordering activities to incorporate Contractor Team Arrangements (CTAs) Reduce procurement lead time Permit ordering activities the ability to incorporate terms and conditions not in conflict with the underlying contract. See also General order Invoice Purchase order Remittance advice Sales order References Accounting source documents Procurement