blackcat, I can't speak to why this particular examiner gave three wm subtests, but when I do it's often because a) there was a marked difference between the standard two wm subtests (ds and lns on the WISC, and ds and ar on the WAIS), b) I want to investigate rote memory vs memory with higher cognitive load (possibly because there were differences between digits forwards and digits reversed), or c) one of ds or lns was spoiled or suspect (in which case that scaled score should not have been reported at all, or with an asterisk). Some examiners cling to the outdated AC(I)D profile, which was once thought to be diagnostic of ADHD; that would require giving Arithmetic.
The score tables in the report should list which subtests were used in the composites. It might be in tiny print under the table of IQ/Index scores.
N, there are two kinds of ceilings being mildly conflated here. There are ceiling rules, which are essentially as you describe at the beginning of your post, and have to do with rules of test administration, and there are test ceilings, which have to do with the limits of the normative sample. A gifted child is more likely than others to -fail to ceiling- as far as test administration, by not receiving the necessary number of zero responses to trigger the discontinue rule before reaching the end of the subtest. Jefferson appears to be inquiring about reaching a test ceiling, which is a situation where the test/norms are insufficiently high level to capture the full range of an individual's ability. This is the situation for which the extended norms become relevant.
I have inserted a link to Pearson's official extended norms, in case your examiner doesn't have them:
http://images.pearsonclinical.com/images/assets/WISC-IV/WISCIV_TechReport_7.pdfAs you will see from the TR, N is correct about the two-subtest criterion for using extended norms.
Jefferson, Coding is fine-motor heavy, which makes it a mixed measure of processing speed. Especially with younger high-ability students, I sometimes substitute Cancellation, which has fewer fine-motor demands.
