“Sounds like something a tower operator would say to the pilots. - Tom”
Sounds like Malaysia Air is signing off from Malaysia control while being vectored to new Vietnamese airspace controllers.
Yes, absolutely. This [link] manufactured MH370 transcript does say Lumpur ATC said first, "good night!". The transcript doesn't really specify who the ATC in contact with. After MH370 signed off from Lumpur Approach after radar separation, who the flight contacted after? Subang area control centre that would endorse them to Ho-Chi-Min ATC?