When the Production is posted, the cost is posted as expected cost to item ledger. The cost expected is calculated by output quantity multiplied by unit cost from Item Card. The cost will remain as expected until the Production order is invoiced. Production Order will be invoiced after finished production order and then run Adjust Cost-Item Entries batch job. Once the production order is fully invoiced, the Completely Invoiced field in the item ledger entry will be ticked.