The set should have 4 Special Defense EVs, not Defense. You got that mixed up. Having higher defense would make the Downloader increase its Special Attack.
From the ability database:
From the ability database:
If this Pokémon is switched into an opponent with higher Defense than Special Defense, it gets a +1 Special Attack boost. If the opponent has more Special Defense, this Pokémon gets a +1 Attack boost. If the opponent has equal defenses, this Pokémon gets a +1 Special Attack boost.