Solution : https://service.sap.com/sap/support/notes/397846 (SAP Service marketplace login required)
Key words : 
additional key words foreign trade, import relevant subcontracting purchase order, lb-component, update prices, program error, advanced correction, subcontracting, statistical, determined, components
Related Notes : 
       
| 747665 | Calculation of GWLB condition, while posting GR for Sch.Agr | 
| 531754 | Import relevant SC order, GWLB not calculated correctly | 
| 446833 | ME21, ME22, ME21N, ME22N: wrong price in subcontracting item |