I'd sit down with the Gifted Coordinator and ask if an exception can be made. I would base my request on the strong score in Math (Advanced) and in Rate of Acquisition and Retention. I'd ask her if she thought that that would be possible with a NonVerbal IQ of 100. And if it were possible, then the rest of the IQ is surely a wild underestimate.
K-BIT II is a screener, and screeners can act a bit funny when facing a 'far from average' sort of mind.
Take a look at the publisher's site:
http://www.pearsonassessments.com/HAIWEB/Cultures/en-us/Productdetail.htm?Pid=PAa32300With KBIT-2, you can obtain a quick estimate of intelligence
It's a 20 minute test. Believe me, if IQ could be determined in a 20 minute test by a Master's level administrator, then there wouldn't be a market for 3 hour IQ tests given by PhDs, right? I like K-Bit 2 to screen-in kids who would ordinarily be overlooked by teachers and parents, but I don't support it's use to screen-out children.
Another tack you can try is to ask if private testing is accepted. If so, which tests and which testers. If money is tight, be sure to ask for the test without the interpretation. Just tell the prospective tester that you want the raw scores and subscale scores and GAI, but not the interpretation, see if they will nibble. If you son is over the age of 6, is the WISC acceptable? (Avoid the WPPSI - whole 'nother story) Sometimes it's easier to find testers to do the WISC. Would the school accept that?
Another way that sometimes works to get the school to do an individual IQ test is to say: Wow, Look at the difference between my child's Verbal and NonVerbal scale. That is statistically very very rare. I'm worried that their might be a learning disability such as Autism. Please start your process to evaluate if he need special education.
Actually you'll have to put that in writing. I prefer to encourage you to go the private testing route, but it the money is a true stopper, then putting on paper a request for a special education evaluation is an alternative.
You can call the company and ask what percent of children get scores similar to your son's. They might have that information, and if they do, I'll guess it's less than 1%.
Sometimes programs will screen someone out, but then let them get a trial in the program, if needed. Test scores are good for most kids, but if you see learning needs that are far above age norms, then you have a gifted kid, no matter what the tests say.
My deeper concern is 'what is the Gifted Program that they are offering anyway?' If he had scored higher, what would they provide and would it solve whatever problems you are seeing.
My guess is that you are signed in under you own name. I would contact the moderator and get a pseudonym and then come back and write (vent) in a non-identifiable way, about what you are seeing that is causing you regret that you didn't go the proactive road.
Lots of gifted kids come from families where 'everyone is that way' and they find friends who have similar kids as well. Then school comes and it's the first truly heterogeneous environment that the family has to function in. What a shock! We call this the distorted yardstick, and it's a very common phenomenon.
Hope that helps,
Love and More Love,
Grinity
This board was recommended to me by a friend who has a gifted child, and who has been telling me for years that my son is gifted and to get him tested. 
We've taken a wait-and-see approach, and now I'm wondering if maybe I should have been more proactive. Oh well... hindsight is 20/20, right?