Solution : https://service.sap.com/sap/support/notes/1178233 (SAP Service marketplace login required)
Key words : 
fiscal year variant, system inadvertently displays, relevant support package, function module fagl_get_account_balance, terms fagl_get_account_balance, selected period, cumulative balance, rpmax reason, program error, solution implement
Related Notes : 
       
| 672255 | Shortened fiscal year/changing fiscal periods |