We had the same sort of problem with the SB-V, CAMom. Our apparently VS DS7 didn't seem all that VS on the SB-V, but he was off the charts VS on the WISC. Since the SB-V is supposed to be good for VS kids, I was surprised by the results. But even our VERY experienced tester said, "This just wasn't the test for him." He advised retesting on the WISC or we would have just let it go, frankly, and assumed that DS7 wasn't as bright as he seemed. I really dithered a long time about retesting.
The toughest SB-V subtest for him was the "What's wrong with this picture" one. Apparently many kids have trouble with that one. If the pictures show things they never noticed or never thought about, they won't do well on it.
Also, if it matters, DS7 ceilinged or nearly ceilinged (most of?) the other subtests for the nonverbal section of the SB-V. (I'm working from memory here, so I'm not sure...) I know that he was looking like a DYS candidate from the first four subtests that he was given, which are the indicators to the tester about where to begin with the other tests. But his scores dropped off markedly after that. It was perplexing, even to the tester.
I dunno if any of that rambling helps...
