It's a complete mess. Take my year 12.
So, last years GCSE's ran as normal, but only the second cohort to do them. She got a bunch of 9's/8's and a couple of 7's and 6's. If she had been this year, she would've got a string of 9's (potentially), as she was working at that level, but screwed up a couple of exams.
This year's ALevel students, will have assessed grades, and arguably will be given the benefit of the doubt, and will "potentially" get better grades that might have got doing the exams.
So DD will do exams again next year, she is currently predicted three A*'s, she might screw up again. So, she will then be competing with this year's cohort, who have deferred, with no exams and better grades, than next year's cohort who will have to do exams, but not have the benefit of assessment.
I am making a lot of assumptions, and nothing is set I know, but it is just what I fear.