How to update the Valution Accounts Defined under Inventory Org Parameters

We are using 'Average Costing method' and for an Existing Inventory Organization that was defined in year 2014, we want to Change/Update the Valution Accounts Defined under Inventory Org Parameters.

Responsibility: Inventory Setup

Navigation: Setup -> Organizations -> Parameters

When we query the existing organization (GXX), under 'Costing Information' tab we have defined the Valution Accounts at the time of initial Inventory Org creation in the year 2014. Now we would like to use a different account, but the fields are not editable for the below accounts:

- Material

- Outside Processing

- Material Overhead

- Overhead

- Resource

I raised an SR and Oracle confirmed that when using Average Cost method, the Material Valuation Account cannot be changed. This is the intended functionality as per teh below document. No data fix would be granted to change the valuation accounts in mtl_parameters.