Sometimes kids are too gifted for the gifted school. We learned this the hard way. My DS is in a private school for gifted and academically advanced children. They say they have children working one to three years above grade level from PK-12th grade. Yet his K teacher swears she has never had a K child come to school reading... including my DS (who reads at a 3rd grade level now). I could tell hours of horror stories about why we're moving on next year.
Frankly, what it comes down to is that there are many, many levels of giftedness. You wouldn't assume that a school that is for special education really understands everything from Autism to cerebral palsy to blindness... yet often gifted schools assume that they can do it all. Some do and do it well.
Ours? It's well designed for kids probably in the 115 to 130 range who are mildly gifted and also do not challenge the system.
That being said, if it's working well right now, don't worry too much about what comes next! You'll kill yourself with all the "what ifs" and "I wonder"!