I have seen mostly Iranian Shias do this. No problem, because in addition to doing the three takbeer, turning the head and saying Salam is also one of the sunnah of prophet. Salat finshes as soon as you say Assalamoalaikum wa rahmatul Allah wa baraka tu' keeping your head straight and your eyes at the place of sajda. This is important.
This is what is done in Surah Fatiha, it starts with praising Allah before reciting the dua, “ihdinas siratal mustaqim” which means “Show us the straight path”. Similarly, we say “Sami Allahu Liman Hamidah” coming up from ruku because when we go down into sujud we are closest to Allah SWT. “The nearest a slave can be to his LordhuelQ9.