From above: Malaysia PM — can say with reasonable certainty ACARS was intentionally turned off before MH370 reached east coast of peninsular Malaysia. Transponder was turned off shortly after.
I thought this information above is not completely clear.
From PM's speech we learnt that the ACARs were switched off before the last contact with the ground when the plane rogered all was OK, then after the last contact with the land the transponder was switched off. I think this should be clarified above..