Solution : https://service.sap.com/sap/support/notes/505738 (SAP Service marketplace login required)
Key words : 
erkrs           xxxx fcode           gen model           rkevrk2o program         rk2oxxxx prog_type       swhen, call function module 'rke_generate_abap', program rkevrk2o, fiscal year variant, longer expect reversals, time period correctly, replace 'xxxx', template program, actual program, transfer program
Related Notes : 
       
| 672255 | Shortened fiscal year/changing fiscal periods |