Try not to beat yourself up. I would have done exactly what you're doing. I really think earlier is better in these educational situations. I'm sorry your son is sick of testing. Probably doesn't help that it's the end of the year. I think the CogAT is more of a fun thinking test though, rather than a test of your knowledge. (Although I don't really know, so don't quote me on that!)

That's too bad that the school wouldn't accept the WISC. I remember being in a similar situation when we were transferring to DS7's current school. He would have qualified for the school with his outside testing, but they wanted to use the CogAT because that is what the school uses. I don't think it's a very long test, so hopefully it will be pain free. I also offered bribes when my DS was doing testing he didn't want to do. Video games, IIRC...