Limitation
MD sub weapon only Effect: Reduce the negative effect of equipping MD as a sub weapon and slightly increase MATK and CSPD.
Passive Effect
When you equip magic device as a sub-weapon, you already have -15% atk penalty to begin. So, leveling this skill can nullify this penalty by +(Skill Level)% atk.
OHS Bonus
furthermore nullify penalty by +5% atk. Amount of MATK = +SkillLvl * 2 + Max([SkillLvl - 5],0). Amount of CSPD = +SkillLvl * 10. Amount of CSPD% = +SkillLvl * 1% + Max([SkillLvl - 5],0)%
Note
max(A, B). Output value is the highest value. If A = 5 and B = 1, then output is A,this skill just change/set atk% penalty into less instead of add +atk%. Just to let you know in case, we had to calculate with Dual Bringer that absolute negative%.