If a pupil does really well in their SATs exams maybe they get 95% their achievement means nothing because virtually all secondary schools do not segregate pupils in year 7 based on academic ability. So a pupil who gets 95% will be put into classes with those who might have got less than 5%, the unmotivated ones who don’t want to be in school and will mess about and slow down the lessons to their own ability.
So that pupil who got 95% put in immense effort only to end up in a class at the level of the lowest achievers. So what is the point of SATs?
What would be better is to give year 7 students their options in year 7 instead of year 10. Then they have a better chance of studying among students of their own ability. Let them drop pointless subjects and do ones of their own choosing.