Restrict the order of success metrics when you are interested in reports only in cases where a certain sequence was followed.
For example, restricting the order of success metrics is useful in the following business scenarios:
This restrains only your reports, not the visitors' display.
You have the option to select landing mbox impression if the entry page (success metric) of your campaign is the only prerequisite. The mbox you choose at the campaign level target is the prerequisite entry success metric. By default this is any display mbox.