Not plot no jutsu haha, he used the same seals used to perform edo tensei since that is the only weakness of the jutsu once someone knows how to release it you got yaself some infinite chakra and an invincible body!
The idea was supposed to be that Kabuto overlooked the flaws to Edo Tensei and casually used it.. so this was probably Kishi's way of showing how you should never use forbidden jutsu carelessly like Madara said. In this specific case, it's just that Madara already knew that using specific hand seals would release him from the jutsu like others said.