I don't know about the age difference - but I agree with the sentiment that the CoGAT isn't a great test. DD17 always scored 99% on ITBS for a grade above, but was somewhere lower on the CoGAT. This prevented her from getting into the gifted program for many years and being bored in the normal classes. We know now that she is probably in the HG+ range, and that this test definitely didn't represent this well...
Having said that, he probably scored a lot higher than 70% if they really did mess up on the age... you should definitely talk to the gifted tester again about that..
