Not just effort values, but from what I remember Fairy has the same base Attack and Defense value so one will usually be higher than the other from IVs alone.
Using Effort Values is a really complicated way to evolve Fairy, it's much easier to either catch a fairy with the Attack/Defense ratio you want, and for getting an Attack = Defense Fairy, use Iron and Protein to make them equal.
Also, Help Me Eirin is the board for official AND Doujin games, this board is for game tinkering/language/bugs/that sort of thing only.