Thank you, Dottie and gratified3!
I forgot to mention in my OP that the MAP math score was in the 89th percentile.
Anyway, your responses have helped me understand both the testing and the discrepancies much better. It's not really the numbers I'm concerned about, but why and you both did a great job of explaining that.
What's interesting is that both DH and I have never really thought of our dd has a math/science kid although for a period of her early years (until beginning of 1st grade) she was all about science, but reading has always been the most obvious strength. Even so, we've both thought of her as more verbally gifted and the MAP scores seemed to reflect that, though I do understand that those are achievement-based vs. cognitive-based constructs. The frustrating thing is that she cannot or perhaps does not want to allow anyone entrance into her mind so that we (parents and teachers) can know that she really does understand what she reads. I wonder if the multiple choice format might be the best approach to getting at what she does know, but I imagine that can hardly begin to approach the depth of her understanding.

With the computer or multiple choice, there's no one to judge her responses. She doesn't even like it when something she's written has been read aloud! I think there's a lot in there that she's not sharing. And we're hardly the kind of parents who interrogate her and force her to do things, kwim? I need to do more reading up on Dabrowski's overexcitabilities as well.
Anyway, we're both finally relieved that we have something "official" that we can bring to her teacher to help her (hopefully) accomodate our dd's learning style. What's interesting is that her kindergarten teacher really pegged her learning style (esp. with respect to the perceptual and memory stuff) - she was eerily spot on - and all of her other teachers since then just haven't been able to understand her nearly as well.