I Personally Do Not Think That It's A Typo And What I Think The Skill Means To Convey To The User Is That Your Summon's Skill Will Increase By 100% (At Breakthrough +1)..But, Your Team's Skill Will Also Increase By 50% Too As Well For Attacking Opposing Teams' Summon's When You Breakthrough This Skill From +1 Skill To +2, That Is