You can only modify the project code of lines if entering this field is authorized by the chosen entry transaction.
If you modify the header project code, a dialog box opens and suggests to transfer this code to the lines of the document, according to the following options:
In modification mode, the management of this code depends on the value of the CTLOPPCOD - Mandatory project control parameter (TC chapter - MIS group).
The PJTSNGDOC - One project per document parameter (TC chapter, MIS group) does not apply in invoice management: invoices, additional invoices and credit memos are onl managed in multiple-project mode. A supplier must indeed be able to issue grouped invoices related to various orders/receipts applying to different projects.
When an analytical dimension type is used for the Project management tracking, then any modification of the project code made at header level will be redistributed to the lines; if the modification applies to a document line, then the dimension code of the dimension type will be reset. This reinitialization is compliant with the Default dimensions setup.
Inter-company specificities: for inter-company invoices, the project code is not recovered from the sales invoice line but from the purchase receipt line or from the line of the source purchase order.