This is easily the gap between a single individual on two different test days. Which is another way of saying that the difference is not useful in assembling a university's incoming class. Once you get above a certain level, the tests decrease in utility to categorize individuals into tiers. Once you get to a certain level of capability, you're broadly talking about smart people who can graduate from your university. Once you've cleared that bar, there's less utility in determining how far over the bar an individual goes versus looking at other ways (which are not measured on a test) in which an individual can add to their campus, class, and the world.
(Source: worked in SAT/ACT/GMAT test prep. Have administered hundreds of sample tests in whole and in parts.)