Thanks for the help, guys.
Something strikes me as odd about this. That classification system is called "my terminology" by the author of the Era 1.5 Ars Arcana, but here Sanderson is calling it "a science on Scadrial", "as they define it on Scadrial", &c that is "more relevant to Scadrial than anywhere else" and "doesn't scale well to the other magics". That doesn't sound, then, like terminology created by a non-Scadrian like Khriss who presumably had knowledge of other worlds' magic before she came to Scadrial... So, am I reading too much into this, or is that evidence against Khriss being the author of the Ars Arcana? Maybe she just borrowed Scadrian terminology, but then how come she calls it "my terminology" and uses it even though it doesn't scale well?