When DS took the WJ-III Ach. last spring, we received "age equivalents" (in year-month format). He wasn't 5 yet, so I don't think grade equivalents are typically provided, but it would seem as though they should be available for a child over 5.
I do not think that you can necessarily compare the SAS scores to IQ, unless they also take the Cognitive Battery. We never took that test, so perhaps someone whose DC did can chime in. Still, those are extremely high math scores and they certainly indicate a current high level of math achievement (many articles available about how this relates to "g"). I assumed that my DS's scores were subject to some inflation because he was young, but since your DS was older at the time he took these tests, those scores are likely more reliable.
