When you cast Utsusemi: Ni with these on, you get 5 shadows but it still displays as 4 in the buff icon. After you get hit and loose 1 shadow, the buff counter remains at 4 then goes down normally after getting hit again.
I just tested these and that's what I found.
Utsusemi: Ichi will display 4 in the buff counter when you cast it as you would expect it to.
BTW these are easy to solo to +2 if you have the patience. I did Ovni for the Voyage Cards, and the caterpillar in [A]Vunkerl for the seals. [A]Vunkerl also drops the actual boots, so you can farm the chests while you're hunting pop items for the iga seal: feet NM.