Customizing Redwood Receipts Page to add a field

Hi Team 

We are using Oracle Fusion SCM Procurement Redwood UI.
On the Orders to Receive → Receive with Details page, the system displays Remaining Quantity and allows users to enter Receipt Quantity. Business requirement is to display an additional read-only field (for example, “Remaining After Receipt”) that dynamically calculates:Remaining Quantity – Receipt Quantity
This field is required only for user visibility and does not need to be stored. We explored Redwood extensibility using:1. Extension Rules (CustomFieldRule) - Only allows enabling/disabling existing fields
2. Page Designer - Layout is seeded and locked, components are greyed out
3. Duplicate Layout - Option not available for this seeded page