I don't have any professional advice for you. But here is a data point that might give you some comfort:
DS was atypical from Day 1. Intense, curious, etc. All good, except when it wasn't. Preschool teacher said "Aspergers." So we got ann assessment for that. No. But the WPPSI said - "very high IQ." The psychologist recommended we re-test with WISC once DS was 6. In the interim, we got several piecemeal tests from qualified, sincere experts that were totally useless for understanding my son's struggles.
When he was 6.5, we bit the bullet, and did testing with a nationally recognized expert on PG/2e. You can read my early posts on the hand-wringing and second-guessing I did during this process. It ended up taking nearly 3 months, and more than 10 return visits. And each visit required a 90-mile round trip drive. I've never had the courage to add up the total cost. I know it was in excess of anything I've seen here. The time and the cost were both astronomical.
And totally worth it. We finally had a full picture of all that my son was struggling with, and all the amazing strengths underlying his struggles.
To be honest, we've never shared the report and recommendations with the school. But that thing is worth it's weight in gold. It gives me backbone and confidence I never would have had without it. It gave me great insights, great ideas, great suggestions for supports for my son.
It's all still a work in progress. But I now know (a) I wasn't crazy. This really is hard for DS, and for us, his parents; (b) He has amazing abilities, and I know how to support them now; (c) he has some real struggles, and I know how to be more patient about it, and help him past them. And help his teachers with them; and (d) did I mention how much it means to know I'm not crazy? Not a crappy Mom? That his Dad and me AND HIM are all dealing with doe seriously out of the box stuff here?
It was long and expensive and the best thing we ever did. Hope it's the same for you - though less expensive
Best,
Sue