DS13 has Asperger's, just diagnosed last year. I am no expert (but am trying). A couple of things I notice in your post:
--lack of empathy is not a diagnostic criterion for ASD and I would be a little wary about a psych who uses that descriptor. That's a really controversial piece in the autism conversation. Empathy and perspective-taking are two entirely different animals and thinking a kid lacks empathy leads you down a different road than thinking a kid struggles with perspective-taking will.
--just because a person doesn't see herself in a helping profession, doesn't mean they don't have empathy. My DS has said he wouldn't want to be a doctor or pilot or anything where "other people's lives depend on you" because of the pressure.
A LOT of non-autistic people would not want a career that was focused on interacting with other people.
--the description of studying social behavior does sound like some anecdotals I've read about females on the autism spectrum. It seems reasonable, too, that a child with burgeoning awareness of being socially awkward and an analytical personality type might utilize this approach. JUST having social difficulties is not diagnostic of ASD.
--as for "waving the 504 flag:" it's probably a good idea to document these things, in case you need the documentation later to advocate. Especially since it sounds like these are occasional issues and not pervasive, it might help you establish some sort of pattern.
--as an observation: the child you describe doesn't exactly sound "unemotional."
More like an unusual profile, with some trouble managing emotions at times. She also sounds like a fairly typical, driven, anxious, gifted young adolescent. It's hard to know what's causing what, isn't it?
It sounds like she's had a really good start and is managing MS well! Don't freak out about the ASD stuff. Whatever it is, it is what it is. If you already have a pretty good handle on where her challenges lie, it probably doesn't matter too much what the label is at this point, since she's functioning well.
My two cents, possibly worth slightly less.
