Here are 3 quotes from the website:
Individuals identified as profoundly gifted, or PG, fall into the range of scores that are at least 5 standard deviations above the average IQ score of 100. Individuals with IQ scores of 175 and higher are considered to be profoundly gifted (PG).
Due to the difficulty in correct identification of profoundly gifted children, PG Retreat’s Application Review Team looks at a combination of ability test scores, performance, recommendations by professionals experienced in identifying PG individuals, and other evidence of demonstration of exceptionally advanced ability in more than one area.
Ideally, applicants to PGR have FSIQ, GAI, or Verbal Comprehension scores of at least 160.
While the site does indicate other things are looked at, it sets a standard that can't be met with the current most well respected tests. Based on what I'm reading it looks like they consider 175 to be pg, but they will consider applicants around 160+ with supporting material. It just seems to me that the organization should use scores obtainable with current instruments for application purposes. No one tested in the past few years could score 5 standard deviations above the mean.