Adding more detail in retrospect in case it helps someone else:

My son did qualify for the gifted program based on a follow up NNAT3. But, they also re-tested with MAP at the end of 2nd grade in reading and math. The MAP testing they had in fall of 2nd grade wasn't adaptive had more of a ceiling. The MAP testing he had in the spring was adaptive… computerized and if you answer a question right, you get a harder question. Removing that ceiling made him look much more gifted and identified him as gifted in reading and math for school.

Ever since, he continues to have high MAP achievement scores in both reading and math.