Full Text Search - Auto Change Tracking

Id like to know a bit about the behaviour of CHANGE_TRACKING AUTO, specifically when the update of the index takes place. In the docs it states 'these changes may not be reflected immediately' but in general when can the changes be expected to appear. Is there merit to updating manually, although the user needs ALTER permission on the table in that case vs. letting SQL Server run it automatically.

Thanks for any help - MikeIn case you or anyone else has found any relevant information about this topic I'd also be interested to hear about it since the documentation doesn't really clear things up.

kind regards,
heinz