Did the new neuropsych. say that he wouldn`t redo the testing now because of the possible re-test artifact or is this more your concern?

I did a bit of reading about this because my DS11 was re-tested with the WISC just under a year after an initial test. Our neuropsych. was not too worried about re-test artifact, and I think it has only been shown to change scores by a couple of points. Unless you need the numbers to be valid for entry into a special program (which wouldn't likely accept the second testing), I don't think re-testing within a year would be a problem and shouldn't change the overall pattern of scores.