Like in the example of Heracross he has like no sp attacks so I used Ev reducing berries to decrease those stats and increase other one by "eating" stat increasers like Protein and iron. When asking a question I said kind of reverse EV training but he though I increased sp attack ev in that case... So what is it called?
Just EV training. But instead of improving all stats by a little, as is usually the norm, you're sacrificing stats you don't think you'll need as much for a more important one.