My son took the OLSAT this year as well. His scores were: Total SAI: 114, 119 Verbal and 105 Nonverbal -> definitely not exceptional.
DS scored much higher on an individual screening test, and I believe he just doesn't perform well in a group setting. In our case, our DS isn't gifted based on the WISC-V, but if I were you, I would definitely request additional screening. Since your DS's math and reading are above grade level, and you believe he needs additional challenges in school, it doesn't hurt to have him evaluated.
