My DD10 does not have an IEP but she does have a 504 for dyslexia/dysgraphia. Like your child, her struggles are often misunderstood and staff thinks that we are a bit crazy to characterize her struggles as a disability. We found that the school readily agreed to extra time but pulled out every excuse possible not to allow for a scribe and/or a reader for standardized tests.
Unofficially, I learned from a staff person that it is a space/staffing issue. Currently, they group all of the kids who need extra time into one room with one proctor for state testing. That proctor is not allowed to speak with the kids outside of a set script. Allowing my kid to have a scribe/reader would mean extra staff in an extra room. In tough budget times, they will not agree to this without a fight. You may have something similar going on in your school/district.
Also, although we all want the best for our kids, remember under IDEA you are entitled to an "appropriate" not the "the best" or a "maximum potential" education. You may want to review this Wrightslaw article on FAPE versus Best:
http://www.wrightslaw.com/info/fape.notbest.htm
