These are some examples that explain how an item acquires its status if broken down into several sub-items.
If any sub-item is Blocked: the sub-project is Blocked
If any sub-item is In progress: the sub-project is In progress
If all sub-items are Completed: the sub-project is Completed
If any (but not all) sub-item is Completed: the sub-project is In progress
If all sub-items are Not done: the sub-project is not done
If an item is To be deleted: the sub-project will receive a status as if the item that is to be deleted did not exist. A sub-item marked as To be deleted will not in any way affect the status of the sub-project.