Except that Doriki didn't count neither weapons nor DFs.
So Kaku's doriki didn't measure his swordsmanship (he didn't even have his swords with him when Fukuro measured their doriki) and his DF inflated swordsmanship.
Basically Kaku's best move, Rankyaku Amanedachi, wasn't counted in his doriki, because it's something he can do only with DF. And DF power up is textually stated to not be measured by doriki.
So by doriki, it's Lucci >>>>> Kaku > Jabra >>>>> the others.
While by overall strength, it's Lucci >>> Kaku >>> Jabra >>>>> the others.