About closing a period
Closing a period in Project Accounting is optional. When you post activity transactions, they are added to the period, year and life-to-date activity balances. The period and year to which transactions are posted are based on each transaction's posting date and the calendar associated with the activity via the activity group. No further processing for activity-related balances or transactions is required.
If you have activated closing control in General Ledger System Control (GL01) for Project Accounting, then you must close Project Accounting. Closing it updates General Ledger closing control so that you can perform General Ledger Period Closing (GL199).
As an option, you can overwrite the posting date in unreleased activity transactions when you close Project Accounting. This allows you to create a clean cut-off for reconciliation. Transactions that are not posted at the time you close Project Accounting can be posted in the next period.