Why are Ma and Pa, and all other frogs on myobokuzan considered as Jiraiya's and Naruto's power; The Ninja dogs are also considered Kakashi's power; Katsuyu is considered Tsunade's and Sakura's power. Every ninja's summon is considered a part of his/her powers. Madara is able to summon the kyuubi at will without having to tame it with his eyes, but when he tried it before fighting the kages, it was impossible because the kyuubi was SEALED. If a summoning is sealed, it is impossible for it to be summoned like in the case of the hokages sealed within the Shikifuujin. Just the same way Oro was unable to summon Minato because of the seal during his fight with Hiruzen, that's how Madara is unable to summon the kyuubi. Some may say that there was no contract made, Yes that's true, just like in the case of edotensei, you need no contract with the person to summon his soul, just a part of his corpse. In this same way Madara, probably with some jutsu is able to summon the kyuubi at will. So, one can say that the kyuubi is also Madara's summon, in the same way with the frogs to Naruto and Jiraiya, Katsuyu to Tsunade and Sakura and so on.
So when rating any form of Madara, (EMS, Rinnegan, Edo, etc) note that without the kyuubi, he's not at full power.
So when rating any form of Madara, (EMS, Rinnegan, Edo, etc) note that without the kyuubi, he's not at full power.