The Periodic Costing calculation uses inventory transaction history and operation transaction history records when processing. It uses the effective date of each transaction to determine if the transaction should be included in the Periodic Costing calculation or not. The system considers only transactions that affect inventory or WIP accounts. Memo type transactions are never considered.

Each transaction processed is assigned a sequential number. This number can be seen on some reports and browses. A record where the sequence number is equal to 0 (zero) indicates that the record was not processed by the Periodic Costing calculation.