In the gifted program in a neighboring town, a large percentage of the kids accepted are Indian immigrants. Based on what I know of this culture, and similar Asian cultures, it's very important to them to achieve in math and academics in general, so the parents are probably supplementing at home, getting their math achievement scores up. Depending on how a district selects students, they may or may not be high-IQ. Some districts don't give any sort of IQ or cognitive abilities test. In this scenario (of the OP), they may actually be more "hot-housed" than the other group.
DD was in a school where the entire grade was imbalanced. It was about 2/3 boys (must have been something in the drinking water the year the kids were conceived!). There have been some classes with 8 girls. Since you've had problems in the past, I guess I wouldn't fight it unless she is really not making any friends...then I would figure out a way to diplomatically request a class change (probably by stating that she's not connecting with the kids and is unhappy). Good luck...