There are two phases, Dig & Identify and Salvage, one has to be finished to begin the other, otherwise why make a distinction between them?! Its like with pharmaceutical companies, they also have to go through phases, or a construction project, also different phases there. Plenty examples. Remember this is an archeological site that has to be fully investigated in a sensitive manner to retrieve as much historical information as possible, so I assume they are going to investigate all mag hits during the D&I phase to be able to "identify" everything. Maybe not the most faintest ones on the outskirts of the map but it would be silly not to research them don't you think, I mean treasure can be scattered there, sometimes in the places you least expect it...