Solution : https://service.sap.com/sap/support/notes/40041 (SAP Service marketplace login required)
Key words : 
<-- insert         ld_betrag   = con_zero-anbtr - zanepa-anbtr, xanbz-dmbtr = con_zero_anbtr - xanepa-anbtr, settle investment measures managed, additional key words ko88, unjustified error message aw639, capital investment measure, error message aa640/641, error message aa641, order/wbs element, main program saplaimb
Related Notes : 
       
| 77032 | AW639, if several depreciation areas for revaluation | 
| 75405 | Inv meas sttlmt -> AW639 or AuC deprec areas wrong | 
| 71699 | AW639: Additional security check | 
| 71408 | Periodic settlem. of cap.inv.measure -> Error AA816 | 
| 70350 | Settling credit memo in the following year of AuC | 
| 66925 | EM: RW022, AW639 during periodic settlement | 
| 60619 | AW639 when settling investment measures | 
| 48895 | Settlm. to fixed asset / AuC -> error message AA641 | 
| 48886 | AA629:balance of transaction type group 10 becomes negative |