Cost Accounting for New Cost Org+ New Cost Book Combination in Current Primary Ledger

Summary:

The client wants to change the costing method from Standard to Actual. They have agreed to the following:

1. creation of new inventory orgs and new cost org and new cost book.
2. Re-upload of the inventory opening stock

We need clarity on the below:

1. Can the old cost org+ cost book combination be disabled/end-dated?
2. Can the new cost org+new cost book combination be linked to the primary ledger to send new accounting entries?
3. Are new inventory orgs required or can we use the existing ones?
4. Are new items required or can we use the existing ones for the new cost org+new cost book combination?