Solution : https://service.sap.com/sap/support/notes/1171092 (SAP Service marketplace login required)
Key words : 
system issues error f5 060 'posting, prerequisites foreign currency due, direct tax posting, exchange rate entered, tax tab page, bkpf-basw3 reason, rounding differences occur, minor difference corrections, implemented due, minor differences
Related Notes : 
       
| 1362108 | Balance error F5 580 in 2nd/3rd local curcy in batch input | 
| 1145030 | F5 580 in second/third local currency in batch input | 
| 1099913 | F5 580 for balance in 2nd or 3rd local currency | 
| 1093088 | F5060 Direct tax balance on Tax screen in Argentina/Peru | 
| 1093085 | FB60 - F5061 balance in 2nd/3rd loc currncy - Argentina/Peru | 
| 717944 | Incorrect tax amount in 2nd/3rd local currency - F5 580 | 
| 645024 | Incorrect tax amount in second local currency |