2959854 - The field 'Product' , 'Contract type' under 'Billing' tab in app 'Plan customer project' cannot be changed

Under 'Billing' tab in app 'Plan Customer Project', sometimes, the 'Contract type' and 'Product' cannot be changed.

SAP S/4HANA Cloud

1. Go to app 'Plan Customer Project'.
2. Go to tab 'Billing'. 
3. Try to change the field 'Contract type' or 'Product'.

The enablement of 'contract type' and 'Product' editing depends on the status of "Extracts" (The line items which are shown in the second screen of Release Billing Proposal [RBP] App) which are created in RBP App.
This is independent of the Billing Plan status. This is done for safeguarding the billing plans from being changed once the user starts editing a projects billing proposals in the RBP App.
These extracts are created based on below actions.

1. Extracts are created for the first time for all existing Server order (SO) items whenever the user clicks on "Edit" button in RBP App.
2. Extracts are automatically created for all SO Items on a daily basis (using a nightly running job) if the extracts were not created by user action (point 1) .

This is standard behavior and normally it is not recommended to change the 'contract type' and 'product' once the stage of the project has been set to 'In Execution'.

Release billing proposal, Billing, Product, plan customer project,  PS_FILL_EXTRACT_TABLES_REPORT, edit, 'contract type' , KBA , PS-REV , Revenues and Eamings , CA-CPD-SS , S/4HANA Public Cloud – Professional Service Projects , Problem