If MH370 turned west from its last known position and, if it passed close to Pulau Perak as reported earlier by the Malaysian authorities, it would be on a track of 255 degrees (approx.). If it had enough fuel for 3000 nautical miles it could have come down about 200 miles south of the Seychelles.
A lot of "ifs", I know, but is this the scenario the Yanks are investigating?