Aeh, thank you SO much!! I feel sort of validated and yet reassured at the same time! That is extremely helpful and your hypotheses actually mirror what we see. She is a bit slow in her work output (is a fast reader, though). And I have a running joke with my husband that she is spelling and grammar disabled!
It's jarring the disconnect between what she reads and understands/can discuss versus the quality of her written work. I'm just not sure what to do about it. We have tried a formal writing program popular with homeschoolers called IEW and we have actually specifically targeted grammar fairly heavily without much benefit. She already feels kind of overshadowed by younger brother and I don't want to make her feel "not smart" or defective.
I will PM you with the rest of the sub scores --thank you!
Any thoughts on a good way to remediate this?