For the score above 160 check the test they are referencing and then ask questions. As AEH said there are no extended norms yet so I don't think a score of 160 is possible. In fact most of the modern tests top out before 160.
I also looked at the PG retreat link. Are there any currently used evaluations that go up to the "five standard deviations above the norm" range that PG retreat desires? FWIW my DD had a GAI of 151 on the WISC-V, FSIQ could not be calculated. She had 19s on matrix reasoning and figure weights and her fluid reasoning score was only 155. I know that she got every question right on figure weights because the evaluator commented that she hadn't had a a kid do that on the WISC V. The evaluator said that she maxed out another sub-test but I can't recall whether it was MR or VP. Either way, no 160s for my kid, let alone a 175.