SAP Message 6A713 - You have not selected all SUs that have to be settled together

Diagnosis
You have not selected all settlement units that have to be settledtogether. Some possible causes:
When you carry out a service charge settlement, all of the servicecharge keys that belong to the same condition type must be settledtogether. You have not selected all of the required keys. The missingkeys are then added and selected in the list.
You have selected a master settlement unit, but not all of itsparticipating settlement units.
You have selected a settlement unit that participates in a master SU.However, you have not selected this master settlement unit or the othersettlement units participating in it.
You can select the settlement units that you want to settle in the nextstep.
The system then checks whether all of the necessary service charge keysare selected using the criteria described above.