User blog comment:IamJakuhoRaikoben/Chapter 473: Red Lightning, Review./@comment-2214433-20160215155205/@comment-86.66.207.93-20160215162446

agree with you, mangastream translation is better and even the jutsu shiki is understandable. Polyusica had Tempester's blood but maybe the treatement was incomplete, during the timeskip Laxus and Freed discovered a way to destroy the MBP and Freed teach the jutsu shiki to Luxus to activate it. Laxus saw in wahl the last element necessary to his cure :

Electricity sent to laxus + jutsu shiki = deactivation of the MBP + Laxus uses the attack = the cure is complete