You gain accuracy every time you gain a level, so in effect yes, ΔLv affects accuracy simply because you would have more if you were of that mob's level.
In Coil you end up fighting mobs who's levels are much higher than your's, so you need enough accuracy on your gear to bring it up to the level it "would" be if you were the mob's level... plus a bit more to overcome the mob's base evasion rate.