I have a very good memory for facts, details, things I've read or heard though that ability (recall of page numbers where particular passages appeared in text) has declined with age. I do not trust my auditory memory, though, and need to do direct A/B comparisons of pressings, for example, within the same time frame, for me to make a meaningful assessment. I have also found that at a certain point, I go into what I'd call sensory overload, and simply can't do the comparisons effectively-- it is mentally exhausting.
That doesn't directly address your question. You claim that you can accurately remember what you heard from weeks before. I also think there are a lot of variables- you mentioned some-- state of power feeding your system, mood (which is in my estimation a huge variable- I don't do any sort of analytical listening unless I'm in the proper frame of mind to concentrate). I am amazed that you can recall with any reliability exactly what you heard in a prior listening session. Perhaps that ability varies by person-- I can usually conclude that a particular dish of food is better than the same dish prepared weeks or months before- that's certainly a sense impression and in that, I trust my memory of the experience. Odd.