when user input in sales order order entry, if there have inventory shortage,

1. Normal item > prompt for back order
2. BTO item  > did not prompt

After order entry input finish, we have this in report,

1. Normal item > back ordered with exact quantity
2. BTO item component  > no back order quantity

After BTO component partial shipped, the outstanding component will back ordered with exact quantity,

when user check the [Quantity on Sales Order] for component item on replenishment position screen, 
it is exclude those with back ordered quantity, that means back order quantity affecting calculation [Quantity on Sales Order]
existing calculation is misleading user for open sales order quantity, checked on IM option for the include and exclude quantity, seems not helping in this,

is there any way to include the back ordered quantity in [Quantity on Sales Order]? 
or where we can find out real outstanding SO quantity easily? 

Thanks