There are times when some transactions are not included in the calculation of Demand and Supply when they use the Check Item Availability page.
The Available to Promise feature gives purchasing and sales department visibility into the projected ship date of goods during the quote and order processes. It enables users to check item availability based on outstanding transfer orders, purchase orders, work orders, and sales orders.
However, similar to any projection the system uses a certain interval in the calculation process. This is controlled by the ATP Lead Time. The ATP lead time is used as a planning horizon for supply and demand considerations in the ship date recommendation calculations. Therefore, if the Expected Receipt Date of the Purchase Order or the Expected Shipped Date of the Sales Order falls outside the ATP Lead Time, then these transactions will not be considered in the calculation.