@boys3
In all honesty I don't know, but I hope so. I think when dd1 was applying (2019) it was a fairly new concept, so I hope they're refining it.
Different universities do use different methods, I believe, so it's possible you could get one from one and not from another.
I really think it is something that should be looked at carefully. On average a state school pupil gets a better degree at the same place to a private, I was told years back. And that will include selective states and poor privates, so I suspect the difference between a good private and poor state is huge.
My dd gave up her 4th A-level subject because the teaching (from a very well regarded state 6th form) was so dire. Or at any rate pretty non-existent. She could have done it on her own, but then she didn't have enough time to study her other 3 subjects. But a friend whose dd was at private did 5 subjects at A-level because the teachers made extra time for her. (tbf I think 3 was better for dd who is an overworker anyway)
My df got to university, the first from his family, from a secondary modern. He took his A-level maths at the same time as his teacher and got a better grade. He was working 3 jobs a week to pay for his transport to 6th form (no school bus once you were over the compulsory school age) and towards university. How would his teaching compare to the local grammar who had a class of maths students every year?
But how do you compare it? And if you have a private school A* pupil, you can't prove that they wouldn't have got those results anyway.
It's very difficult to be fair, but I do think (knowing that my dc won't get contextual offers, even though they're not at private) there needs to be something in place to even things out.
I do feel for people who have, for various reasons, struggled to put their dc through private school, to find that they are at a disadvantage at application time, and I can understand that they feel discriminated against. But there are many 17/18yos who have worked hard for all they can achieve with their current situations and will fly at uni, and deserve a little leg up. My df would have been one.