Just in from the BBC, some of which confirms the WSJ report (times are UK):
http://www.bbc.com/news/world-asia-26659583

British satellite company Inmarsat tells the BBC there were very strong indications 10 days ago that the plane would be found either in the southern part of the Indian Ocean or in Central Asia, and not in the South China Sea or the Malacca Straits where Malaysian authorities continued to search.

15:03: Inmarsat says it learned on 11 March that the plane had continued to fly for seven hours or more and that it was very unlikely to be in the area where the Malaysian authorities were searching. Inmarsat has made the information public because of concerns over the way the search operation has been handled.

15:12: The information Inmarsat has revealed to the BBC about the data it gave to the Malaysia authorities matches a report in the Wall Street Journal published earlier on Thursday. Inmarsat claims the Malaysian authorities continued to search in waters close to the plane's point of departure despite receiving satellite data suggesting that the plane continued to fly for several hours after losing contact with air traffic control.

15:21: Based on information released by British satellite company Inmarsat, Malaysian authorities waited at least three days before publicly acknowledging data that suggested the plane had continued flying for several hours after it lost contact with the ground. Correspondents say the revelations are likely to increase the pressure on Malaysian authorities, who have been accused by the relatives of those on board of withholding information from them.