Multiple spellings of the same word, especially multiple unique misspellings, is a clinical indicator that I would not ignore, even if she is one of the better spellers overall in her class. Most poor spellers use the same misspelling repeatedly in any given session of writing. (As a result of weak spelling strategies.)
Does she understand multiplication, but struggle to memorize them to the point of automaticity? Those are two different situations (poor conceptual grasp of multiplication vs poor fluency with multiplication).
Anxiety does have impacts on attention and working memory, and certainly is a reasonable hypothesis. There are also some indications from MRI data that it has some negative interactions with mathematics.
Additional information I would look into would be spelling skills: Phoneme/Grapheme Knowledge on the WJIII, Spelling on the WIAT-III, KTEA-II/III, WJIII/IV, or TOWL-IV would be some options. Academic fluency skills: Math Fluency, Writing Fluency, Reading Fluency on the WJIII/IV or KTEA-III, or Math Fluency, Oral Reading Fluency on the WIAT-III, or various dimensions of oral reading on the GORT-5.
Basically, I think you need more information to be able to meaningfully reconcile the two assessments you have had so far. This information should include academic achievement testing, including some of the areas I've listed above, and probably slightly more in-depth social-emotional assessment and executive function, given the Dx of GAD. Whether you pursue additional assessment depends largely on how unhappy or stressed the existing schooling situation is making your daughter and your family as a whole.
