Periodic Costing ensures that the inventory account is evenly balanced when you:

The Periodic Cost calculation program creates adjustment transactions to balance the amount in each inventory account for an item based on the calculated cost of the item. This results in the GL account balance accurately stating the inventory value associated with the account. It also ensures that the accounts are balanced when you summarize the inventory quantity in the locations for that account and multiply the summary by the calculated periodic cost for the item and that the summary is equal to the account balance for the item.

You define a cost revalue account to offset inventory accounts balancing transactions. You define the cost revalue account in the Cost Revalue Account field in Periodic Costing Control (30.5.24). The system only uses this GL account for the rebalancing, and it should always have a zero balance.