When generating collective purchase orders, you can have the system check if any stock has been procured for the order items involved. This allows you to use existing stock on-hand and planned issues and receipts as available quantities and reduce the quantity required in the collective purchase order by this quantity.

You can use this function if, for example, you are switching from putting away a particular article into storage to cross-docking it in the distribution center. If, at the time of switching over your method of processing, there is still stock on-hand and open purchase orders still exist, you can have the system take them into account and thus avoid having to procure more than you need.

To check if stocks have already been procured, the system runs an availability check based on quantities that are available to promise (ATP), without taking any replenishment lead-time into account. There is no comparison made with any contingents or plans.

To activate the check, set the indicator for checking for stocks already procured on the initial screen for creating a collective purchase order. You also have to enter a check rule for the availability check.

In Customizing for the check rule used, you can specify which stock types (such as stock in transfer, stock in quality inspection), receipts (such as purchase orders) and issues (such as deliveries) are included in the availability check.

The exception to the stock types is the unrestricted-used stock. You cannot control whether it is included in an availability check using a check rule. This is usually taken as an existing receipt, independently of the check rule.

You can exclude unrestricted-use stock from the availability check by setting the "Exclude stock" indicator on the initial screen for creating a collective purchase order. Stock can, however, only be excluded if you have not activated requirements planning for RP areas in Customizing in the Distribution Resource Planning (DRP) section.

During an availability check, the system checks availability on the delivery generation date for each schedule line in an issue document item. If a quantity is available on this date, the system proceeds as follows:

Quantity of collective PO schedule line (new) = quantity of collective PO schedule line (old) + quantity of issue document schedule line - available quantity

The quantity procured in a collective purchase order item is reduced by the quantity already available.