1. PO Qty
2. DO Qty (Order for Warehouse to Deliver Item)
3. SURAT JALAN (SJ) (Delivery Item)
4. SISA means Balance.
DO Balance means QTYPO - QtyDO
SJ Balance means QtyPO - QtySJ
One Item, can have several DO, and one DO can have several SURAT JALAN
There comes the problem, in the screen shot DO is 600, and SJ have twice delivery, which is 200 and 400. And both of them came from 600 qty of the same DO. Thus the DO Balance is minus.