Solution : https://service.sap.com/sap/support/notes/1611321 (SAP Service marketplace login required)
Key words :
company code tax calculation takes place line-, document tax line items, newgl document splitting, ttxd-xtxit = 'x', tax relevant, tax amount, accounting document, terms xtxit, accounting transaction, bseg-txgrp
Related Notes :
1314818 | BSEG-tax line items not summarized |
1009374 | NewGL: Prevent split of taxes if calculated line-by-line |