Solution : https://service.sap.com/sap/support/notes/1392122 (SAP Service marketplace login required)
Key words :
setting 'calculate tax line, ttxd-xtxit = 'x', 9 line items, tax amount, terms xtxit, transaction miro, purchase order, general ledger, document balances, 'detail' button
Related Notes :
| 926481 | FB60/FV60: Balance error with manual tax |
| 772344 | FI-EnjoySAP: Final amount proposal incorrect |