It would make sense to have another function/drop down option for the Sales order line deletion policy (SalesParameters.SalesOrderLineDeletionPolicy) within AR Parameters. The addition would provide a third option which would be "Decrement the referenced purchase order line per the referenced Sales order line quantity" which would produce a pop-up, similar to "Delete the referenced purchase order line entirely", when removing the sales order line or reducing the quantity on the sales order line, and, when selecting "Yes", the referenced purchase order line quantity would be reduced, and, if reduced to 0, the line would be removed.