Need to get packing date.

 Hi,

      We need to get packing date for order lines which are packed. We have the requirement of showing the quantity of items which are packed but not shippped. For this we thought of using the wsh_delivery_details and if the line is associated with parent_line_id , then we are considering that as packed and the quantity on the delivery detail id as the packed quantity, is this assumption correct or not? And if it is correct then we need to get the packed date of the detail id so that we can show the total quantity of the items which