Sorry, I haven't been online here much so I'm slow in replying. I guess that whether it is worth the money for outside testing depends on whether it will open doors for your dd that might otherwise be closed and that really need to be open and also whether you have other indications that she is gifted beyond the high reading achievement on the ITBS.
In regard to the former, it sounds like your GT program isn't that robust, but does it become better later and would being in the program now make it more likely that she'd get into the later programming?
Regarding other signs of giftedness, I guess that I'd want to know if you have a family history of giftedness with people who've had actual IQ tests done not just group screeners or some other strong indicator such as qualification for groups like Mensa or something like that. I'd also look for other more objective signs b/c I do find that the personality signs of giftedness are much like the square/rectangle analogy: a lot of gifted kids may be intense, sensitive, perfectionists, etc., but all sensitive, perfectionistic, intense kids aren't gifted.
What did her milestones look like as a young child, particularly those that are not motor skill related as walking early, etc. is less correlated with intelligence than, say, talking early? I'm not necessarily expecting you to list that all out for us, but am just putting it out there as stuff to think about in getting a feel for whether the money will be well spent confirming something you already know to some extent vs. something you suspect but are less sure about.
I hope that all makes sense!
Regarding whether the group test scores will come out the same - who knows! People certainly do prep for those tests and see scores bumps from doing so and you could do that. However, the kids who I've seen, anecdotally, who are pretty consistent on group tests are high achieving, in the box thinking kids who are not necessarily gifted and who are prepped for the types of questions they are going to get as well as truly average kids. As someone else mentioned on your other thread, HG+ kids can be a lot more erratic on group tests and get much lower scores than their IQ scores.
I, personally, only have one child who has ever taken the CogAT and she only took it once, so I don't have a good pool of gifted kids for whom I know the scores. I do know more about the kids who were close to getting in to our GT programming and had to be retested b/c they didn't quite make it and they fall more into the category I mentioned above: had been prepped before the first testing, fell a bit short and were retested and made it the second or third time with more prep. They are high achiever kids who fit the school expectations well, but not really gifties. All bets are off when dealing with a gifted kid, especially one who has already tested lower than his/her ability on a group test b/c that is a good sign that something didn't work out the first time and just hothousing the material might not be enough to bump him/her over the line the second time like it might for a more typical kid who knows how to color inside the lines better, so to speak.
