The mtDNA of AA matched FS relatives, but with a slight variance, which means it was less than conclusive. the report was that it was PROBABLE she was related, but not for sure.
Don't forget also, that the mtDNA showed without QUESTION AA could not be related to Alexandra Feodrovna. (Im still waiting for anyone to show me the science that says otherwise...people claim it, but so far, no one has shown us one single reliable report otherwise.)
FA, you are correct, if AA's mtDNA showed a mismatch with the Victorian DNA then it is conclusive evidence that AA could not have been a Victorian descendant, i.e. Anastasia (unless they suspect conspiracy). But even if AA's mtDNA exactly matched Victorian DNA or FS's relatives, that would not conclusively prove that she was AN or FS. The fact that her result was inconclusive for FS's relative(I didn't know that, I thought it was conclusive) tells us that she probably wasn't FS. I think people are confusing two things here: the fact that you
cannot prove someone's identity with DNA and the fact that you
can disprove someone's identity with DNA. When people talk about DNA tests being more accurate now than 10 years ago, I think that they are actually getting the two things mixed up. Yes, to
prove someone's identity they now have a higher criteria, but not to disprove it. So yes, they now use more stringent DNA matches (more strands have to match than before) in criminal cases, but this is when they are trying to prove someone committed some crime - trying to prove that this person was the criminal. In AA's case, it was just the opposite, they were trying to show
whom she was not and that is a lot easier to do. You can get a false positive DNA match, although this is rare, but you can't get a false negative(as far as I know). If the DNA doesn't match then this person is not the person they claim to be. But if the DNA matches, then they still may not be whom they claim to be because you may get a false positive or you need a more stringent test. That's all. I don't know if this makes any sense, I may have confused people even more! :-/