"Only 50 bodies floating on the surface were recovered when the plane crashed 1,500 miles off the coast of northern Brazil on June 1, 2009.
Another 178 are still missing and up to 100 of those are thought to be inside or around the wreckage itself."
78 passengers unaccounted for in the wreckage or recovered. Is there another portion of the wreckage somewhere else than the main field??
You can be pretty sure they had found all the wreckage at the conclusion of phase 4. They located the wreckage very quickly and certainly had the time and the budget to keep looking if there was a major piece missing.
They would not have found all the bodies on the surface. Remember it was a huge search area, and it was out in the middle of the ocean so they were searching by ships and fixed wing only. A body is not that easy to see from a fast moving aircraft, and you can only see a couple of hundred metres at best from a ship.
This is yet another good reason to leave the remaining bodies undisturbed. Were they to recover all bodies, there would be angst among the relatives while waiting to see if their loved one was recovered. Better to avoid that scenario.