Solution : https://service.sap.com/sap/support/notes/1339273 (SAP Service marketplace login required)
Key words : 
batch-dependent quantity conversion factors exist, terms active ingredient management, product quantity management, purchase order item, price determination reason, conversion factor, order unit, price unit, supplementary condition, condition unit
Related Notes : 
       
| 1226419 | Batch information in PO item not passed for pricing | 
| 668906 | ME22N: change batch : weights and volume not re-determined | 
| 529748 | Copying a purchase order item with batch | 
| 390242 | Conversion factors are not determined for batch |