Change Average Cost Calculation from Inventory Org to Cost Org level

Our client wants to change the Item cost calculation for few Cost Orgs from Inv Org level to Cost Org level.

Below is our understanding:

1. Old items that are costed already, will continue to be costed at the Cost org - Inv Org level only.
2. Once we create a new Valuation Structure, Valuation Units, Cost Profile and update the Default Cost Profile of the Cost Organization, new items will be costed at the Cost Org level.

In oracle documentation it is clearly mentioned as below:

"After transactions are performed against a valuation structure, you must not change the valuation structure by adding or deleting costing attributes. Doing so could cause unpredictable results, especially if some transactions are already costed using the original valuation structure."