If the school will take private testing and you are able to do it, I would go that route; the CoGAT just seems too unpredictable to me. My DS7 took it this past January and recieved a score of 127, which isn't in the gifted range for the test. We had him tested privately in August and he is HG+. The discrepency between the scores was huge. I know other people have had good results with the CoGAT, but it just really seems hit or miss (even more so than individual IQ tests) to me.
If they won't accept anything else, then definitely use it, but if the results are lower than you expect, it's most likely the test (and from what I've seen high results are almost always accurate with the CoGAT).
