The assumption, working premise if you will, was/is that the bodies of the two first officers were retrieved with their seats. And that these were the bodies sent back to France for DNA identification. The successful results of the testing led the court to authorize recovery of the other bodies from the abyss.
The fourth seat in the cockpit was also retrieved at the time that seats 1 and 2 were recovered. There was wondering at the time on why the fourth seat and not the third seat was retrieved.
Three seats, two bodies. But the new information in interim report 3 raises the possibility, likely small, that the first two bodies recovered were those of the PNF who was belted in, and the wife of the PF who was sitting in the fourth seat, and also belted in. And that the body of the PF was not recovered (at that time) as he was not belted in. (The captain is now presumed to be standing or perhaps seated unbelted in the third seat.)
As the fourth seat was located directly behind the seat of the PF, this could explain why the PF was not belted in, as he could more easily turn to converse with his wife.
From a conversational context, when the PNF explains the smell of ozone, is he saying that to the PF or to the wife of the PF, who is a physics teacher?