Doesn't seem worth the fuel.
These black boxes from what I heard stop pinging after a month. Can we stop then, and just move on in life until one day some seat cushion washes up in California and have a moment if silence? Without it pinging, just how wide an area can a ship in substantial depth detect a wingtip?
I realize you didn't, but if you ask me, they should just frame that copilot, say they found on his flight simulator evidence that he intended to make that "deliberate" turn every night, disabling the transponder with the ctrl+shift+T combination and purposefully crashing hours later each time in a different location, with known Islamic terrorists on his WhatsApp and Skype, or a suicide note, then call off the hunt, pay the families off for failing to screen this guy effectively, bam, there's your closure, problem solved.
/insensitivity