Thanks for the replies.

DS is in 7th grade (math is Pre-Algebra), and in a smaller charter. I've heard that many folks are much happier using the program independently as opposed to the charter/virtual academies. Certainly, the larger part of our frustration is with the local level school, but we're...puzzled(?) about his flying through the first semester of the k12 math with minimal effort, yet encountering concepts on another assessment that he's not yet seen in his current course.

Perhaps it's just a difference in curriculum or the definition of "Pre-Algebra"...