I think the whole concept of IQ tests is outdated, and I believe those tests (like Stanford-Binet) should be discontinued as measures of intelligence.
In the past two decades, science has discovered so much when it comes to the brain, intelligence and learning, that the typical IQ test is rather a joke. IQ tests are NOT accurate measures of how well someone will do in school.
Intelligence is a broad concept, having to do with curiousity, independent thought, being able to grasp multiple sides of concepts, and things of that nature. Intelligence actually has little to do with how early someone learns to read or do math. Those skills are just two of many skills that people have, and grasp at different ages. There are children who can grasp musical concept or art concept at an early age, and reading and math are comparable to that...not a basis of determining intelligence. It's just an indicator of what part of their brain has become more active as they grow, and some people excell in some areas and some in others. This is not true intelligence.
If your child is doing well in school, great. If they're not, try to determine why and correct it by finding appropriate classes for their style of learning. The same goes if the chile is excelling in school...find classes to challenge them.
The very fact that there are so statistically many more high IQ/gifted children shows the flaw in the old-fashioned IQ measurements. Society has made children more knowledge savvy, but that isn't an indication of intelligence.
Progressive psychologists are now campaigning to do away with Stanford-Binet type tests, and are developing more accurate and up-to-date ways of measurement. And these, they argue, should only be used for diagnosing possible true highly intelligent people, and truly low intelligent people. These tests shouldn't be used just for the heck of it.