If they need to cut program costs, then the only version needed is the carrier based version. You don't need the VSTOL (oh, wait, only it can escort the Osprey????) and you don't need one that can't land on a carrier.
Joint <-- seems to have been forgotten.
You can fly a carrier based aircraft from any airstrip, but the "airfield only versions" don't make the carrier cut.
How hard is this to figure out for the "Oh So Smart" folks in DoD?