My dear Brothers and Sisters. Do you know why there is so many duas etc that we say in salah? Why there is so many versions? Because hz. Resulullah Sallallahu Aleyhi wa Sallam used all of them. for example if you say in sajda "Subhana Rabbi al 'ala" 3X you can add for example "Rabbi ghfir lii wa 'ala alideyna". According too views of Shia 'Ali only sura Fatiha in first two rakats is fard, rest doesn;t have to exactly the same. In most cases this thinking is... right! In every sunni mazhab there is a little bit vesrion of taslim (at the end of salah). Why? Because hz. Resulullah (Sallallahu Aleyhi wa Sallam) was using several versions. He was using his own dua'a (what he needed at the moment) in e.g. sajda, ruku, etc This variety is mercy of Allah Subhanahu wa Ta'ala given to us.