Yes, they will accelerate if the overall math knowledge is high. My daughter is not very mathy so for her it will be a nice way to fill in the holes and move forward as she is ready. She's ahead in certain math areas but not others.

My other dd, (dd7) is accelerated in a program that uses Math Expressions by H. Mifflin. The spiraling is there as well. That's the reason her teacher thinks she'll continue to be ok even though she is still a bit behind (since they will revisit the topics.)