I don't have any experience with that test or a gap that large but my DS had a verbal-nonverbal split both when he was 3 and 6 on the Weschler tests. (on the WISC he was around 115 verbal and 140 something non-verbal.) They thought the non-verbal score was an underestimate because one of the subtests for non-verbal ability wasn't accurate in his case due to motor issues and a brain injury...so I'm not sure how big of a split it really would have been had the results been totally accurate. I believe the lower verbal ability was partly because he did not want to answer the verbal questions due to a bit of test anxiety/shyness, but also because he is twice exceptional and has developmental dyspraxia/apraxia of speech and had some mild speech delays relative to "typical" kids (but huge compared to himself and his other abilities). The gap seems to be closing as he gets older (I believe verbal ability keeps rising to become more even with non-verbal ability). I have no idea what is going on with this other child, but it could be there is a subtle disability that is deflating the verbal score, he has uneven development, or he was just more focused or motivated for the non-verbal section. I don't think IQ tests done on 3 year olds are all that predictive, so make sure the parents understand that.
