Concerning Oei Bizen smiths, clearly Fujishiro is inconsistent. Taking into consideration that the best smiths of a given period are rated Saijo saku by him, The san mitsu being the best smiths of the Oei period, they should by all means be rated Saijo saku. There are of course quite a lot of blades by Yasumitsu and Morimitsu which are Juyo, Moromitsu blades are rarer. Nevertheless, compare Sukesada prices to Yasumitsu/Morimitsu prices, the difference is not in proportion of the difference of level saijo/jo.
In Japan, Oei Bizen smiths are rather rated jojo/saijo taking the prices they are sold. You will find more short blades (tanto/wakizashi) and the tachi when ubu are sold at a high price.