I'm trying to dig around for our recent Gates-MacGinitie for DS6. He was also in the 99th percentile overall and missed 3. I'm going to agree with "momtofour." My "guess" is that these results are so tightly clustered (with about 80 or so questions) that there isn't much margin for error. So... even missing a few may drop the percentile rank.
For instance, my son missed (it looks like) 1 more than your daughter and they have his reading comprehension level at the middle of the 2nd grade. As his mom, I am watching him read and enjoy books this summer with a lexile anywhere between middle of 3rd grade through 6th grade (a wide range).
