Solution : https://service.sap.com/sap/support/notes/214740 (SAP Service marketplace login required)
Key words : 
-paid tax retro reason, terms 1999 year-end, taxable cash earning, relevant master data, payroll driver determines, payroll driver, payroll data, partial retro, current retro, applying notes 188465
Related Notes : 
       
| 316469 | Partial retro over reversal for releases 46B and up | 
| 193352 | Entries in BAL not properly accounted in retro | 
| 188465 | Entries in UNB not properly accounted for in retro |