Solution : https://service.sap.com/sap/support/notes/210214 (SAP Service marketplace login required)
Key words : 
additional key words 4-4-5 rule, fy    period    portion2000                1         312000                2         282000                3         312000                4         302000                5         312000                6         302000                7         312000                8         312000                9         302000                10        312000                11        302000                12        31, prerequisites customizing solution, regular fiscal year, regular year, fiscal year 2000, period weighting, shortened year, shortened year 9, reduction rules
Related Notes : 
       
| 672255 | Shortened fiscal year/changing fiscal periods |