Business scenario : Organization wants to enter the Sales orders for the customer but doesn't want to commit the inventory during the order entry process. The default AR parameter is set to "Manual". User completes entering sales order lines which can be around 30 to 75 lines order. Turning the header level reservation parameter updates line level but this process never reserves the inventory. So if MSFT adds a new batch process to start reserving the Sales order for NON WMS warehouse that will be beneficial for organization that perform such business.