Solution : https://service.sap.com/sap/support/notes/1148384 (SAP Service marketplace login required)
Key words : 
attached source code corrections, shortened fiscal years based, shortened fiscal year, fiscal year, t090na-xrafa, system determines, smaller number, depreciation key, depreciation calculation, depreciation
Related Notes : 
       
| 672255 | Shortened fiscal year/changing fiscal periods |