Solution : https://service.sap.com/sap/support/notes/430684 (SAP Service marketplace login required)
Key words : 
e_bezwrt =   i_ganlc-kansw + i_ganlc-answl +             i_ganlc-kmafa + i_ganlc-mafav + i_ganlc-zusma +             i_ganlc-mafam + i_ganlc-mafal +             i_ganlc-kaufw + i_ganlc-aufwv +             i_ganlc-aufwp + i_ganlc-aufwl, call function 'date_to_period_convert'      exporting        i_date              = t_anep-bzdat        i_periv              = t001-periv      importing        e_buper              = nper        e_gjahr              = ngjahr, perform copy_tables tables l_anlc l_anep l_anea l_anlz, e_bezwrt = i_ganlc-answl +, e_bezwrt - i_ganlc-answl, lokale kopien der internen tabelle bilden, message id 'aa' type 'i' number 747, statics setzen  sta_bukrs = t_anep-bukrs, read table t_anep index 1, enter user defined base
Related Notes : 
       
| 524701 | linear depreciation - only for Poland | 
| 92260 | Incorrect depreciation for subsequent acquisitions |