User blog comment:Godisme/My Take on Isshin/@comment-1769234-20100329185017

Ichigo may posses the spiritual power of two captains with his hollow mask like how Aizen Yamamoto and maybe even Isshin power is at that level though has of now has not developed it to that level without using his hollow mask to enhance the strength of his spiritual power. As for the Uliquiorra Segund Etapa being defeated by Full Hollow Ichigo it is believed via Toshiro's Silhouette of a Vasto Lorde in episode 115 of Bleach it could be that Uliquiorra was a Vasto Lorde level hollow thus having the spiritual ranking much higher than an average Captain and that the full hollow transformation on Ichigo made him have the power increase of a Vasto Lorde though these are all just theories and not proven facts.