Quite some number of pages back I made a post that has disappeared as completely as MH370.
The initial press release from MH stated clearly that the a/c lost contact with Subang ATC at 0240 local time. This was also posted on page 1 of this thread. It has not been redacted to the best of my knowledge.
The transponder supposedly stopped at 0121 local. One hour and twenty minutes creates a rather large search area from the point at which the transponder ceased transmitting.
Clearly something is known that has not been shared yet.