I'd say ask the school if they can give her the test. If not, then you have to decide if it's worth the cost to you. We're going through the same debate here, if that gives you some moral support...I guess it just depends on your needs. If you have a good educational solution for now, then it's harder to plunk down the cash, I think. At least, it is for us now that we're happy with home schooling.
I just videotaped DS6 doing a math lesson. I don't know if it's persuasive, but it's better for the portfolio than the mostly nothing that I've got... I'm hoping that seeing this young HG+ kid in action will be worth more than all the mute worksheets there are.
He and I have also discussed his writing one of his "books" (usually about Transformers or an "I Spy" book) for the committee. We'll see how that goes.
<shrug>