I have power leveled extensively with Fire/Electric mages since the SE glitch came around. From experience LK does not seem to affect the failure rate of SE. It is always around 5% no matter what.
All magic skills will miss more if your LK is lowered, not only SE, but unless you are using game equips against much higher leveled mobs, you will rarely miss.
Recette - Witch 400 | EmiriTachibana - Diva 400 | SakuraHiiragi - Champion 35x | AnaJessicaAyano - Soul Master 26x | LeslieSun - Witch 26x
Bye Bright Shadow Japan, I will miss you all and my bunch of characters very much ~~