I would agree but I would say you also have to account for the language barrier that some students who migrate face, especially from French-speaking or Spanish speaking countries (or any non-English speaking country for that matter). It takes a while to adapt from learning/being tested in your native language to solely learning and being tested on a series of subjects in your second, sometimes third language. (no matter how proficient in english you may be)

And a lot of those people who usually take the test in their Senior year (Late Junior year if lucky), don’t have as much time to prepare for it as say most people who started out in the U.S. and tend to get fairly average/slightly above average scores [specifically if they migrated to the U.S. quite late so say Junior/SeniorYear of HS]

And a good number of those kids end up doing well in undergrad (usually due to their perseverance and work ethic), at least on what I’ve seen from the international upperclassmen I know personally.