This is more of a what-we-have-done instead of what-would-you-do. We had a situation where DD's score on a test was completely out of whack with expectations, and in discussing it at home, it was clear that we were just guessing, and the only way to find the right course for advocating was to get that test.

In our case, we found a section of the test that really didn't belong (wrong grade level), and some simple questions our DD had rushed through (opposite test-taking personality of yours), which could be cleared up through some coaching on test-taking strategies.