Regarding aptitude tests which use differing cut-offs for different subjects, it may be useful for someone to note that the PAT also works this way. It is used to assess applicants for physics, engineering and materials science.
For physics, use of the PAT is fairly brutal and candidates are interviewed if they are in roughly the top third of scorers. (Some allowance is made using contextual data.) For engineering and materials science, the cut-off is not so rigid. It is apparently possible to get an interview for those two subjects with a less-than stellar PAT score, if everything else about the application is high quality.
DS survived the PAT last year and is happily settling in his first year at Oxford. Good luck to all this year’s candidates.