Special order items are excluded from receiving a forecast, but so does the "exclude from forecast" setting option.
So what is the difference?
The behavior is identical, whereas the drivers for different marking are mainly master data driven. as it can be beneficial to highlight regular stock items from special order items, regardless of how the demand is derived for a given business.
So what triggers replenishment in the order calculations?
The order behavior of both special order items and items excluded from a forecast, are essentially the same: demand is derived from any of the following: open sales orders, data inserted into the sales plans, data inserted into the promotions plan, min display stock. These factors will trigger an order quantity if the item does not have enough stock to cover.
Special order items: Are items that we don't want to hold regular stock on unless there is a committed demand from a customer, through open sales orders.
Exclude from forecast: Can be helpful in phasing out items, before closing them in the ERP.
There may also be scenarios where excluding the forecast and manually controlling the demand is applicable for a business, for example a production plant that plans upcoming demand on finished goods, solely based on the production line capacity for the next quarter. In this case the production planner will want to control the demand and derived order needs on the BOM components. The items excluded from a forecast are in this case live and kicking regular stock items, and should not be marked as a special order item.