Solution : https://service.sap.com/sap/support/notes/482538 (SAP Service marketplace login required)
Key words :
symptom create bos type sales order, create service entry sheet, execute billing due list, billing due list reason, billing due list, assign wbs element, sales order, wrong billing, item category, relevance forbilling
Related Notes :
| 513810 | BOS Sales document: Items can be billed twice |
| 495053 | Status of BOS sales document is Open |
| 178586 | Incorrect planned revenues for resource related billing |
| 167767 | Planned revenues for items not relevant for billng |