my thought is ===== lower ranked smiths sometimes had a great day and made a great sword, and sometimes a high ranked smith made something that with a few polishes showed some issues. Personally i prefer a well made sword by a lower ranked smith, some of my favorites are Chu-Saku or ChuJo- Saku, but from a marketing standpoint the higher ranked smiths will always bring higher prices. Fujishiro-sensei had the opportunity to see many swords by a maker so he is ranking the whole of a smiths work, not an individual sword. Also being Japanese there are other factors that go into a ranking, like how the smith was thought of in the past, how famous he was or how well known, also some smiths benefited from sponsorship of powerful people and that helps. Sort of like the NBTHK today, you can have a masterpiece but if the maker has never had a sword pass Juyo that sword won't, at least it won't if i own it, if you are an important person you might have a chance of setting a precedent but not me.
John, did you see the display in Chicago? The tachi with the horimono is one of my favorites and about perfect in every way but it won't pass Juyo (it is YuShu-saku)
Darcy puts it better than i can, check https://yuhindo.com/ratings.html