Locking a period

Not sure if the documentation is incorrect but, regarding locked periods (http://docs.oracle.com/cd/E17236_01/epm.1112/fcm_admin_11122300/frameset.htm?launch.html)

"When work on the schedule has reached a stage when follow-up work is all that is required, you set the status to Closed. You cannot add new tasks to a Closed schedule, however users can continue to work on tasks that are not complete. You can reopen a closed schedule, which changes its status to Open.

When all close tasks are completed, you set the status to Locked. You cannot edit a Locked schedule, or set it back to Open."