Possibly. My suspicion is that less people have taken multiple professional IQ tests (I've only taken one professional one) than multiple SATs (I think I took it three times, at various ages). I score significantly better on the Raven's subtest than on other subtests, and so my IQ.dk score was significantly higher than my professional IQ test last year- but this year I only reported the professional one, because that was all that was asked for. (I might not be representative.)