You’ve listed them all, really.
What I always say, and really believe, is that these places are a significant step up in speed and intensity which takes some getting used to in any case. Add a cup if they are boarding. Add another cup if they have athletic potential. It takes a while to adjust to these places and the further away what might be a bumpy first year is from the college application process, the less impactful it is. Reclassing just gives you a longer runway. There’s a big difference between starting the race as a less mature 14-year old and a more developed 15-year old, and that difference plays itself out socially as well as academically, impacting the kid’s overall experience.
Plus, larger entry class.