[@Sep] Well, from a tactical point of view, when you see 12 gigantic ships taking off, you want to make sure you send at least something that can take down all 12 of them. So one ship that can deal out, what was it, 11% of a shield? That wouldn't cut it. You'd take down one, maybe two, before they reached the eye. 

So maybe this one is just a nail -- a ship meant to pin down a few of the arks, while more of the ships are getting ready to phase into the earths atmosphere to take down the rest of the arks.

That's just what I'd do, if I was a gigantic organic ship.