Yes, it will not always raise +4 each time. I'll explain EVS to you.EVS are attributes which give bonuses to a Pokémon's stats and improve differently depending which Pokémon they defeat. These bonuses, in the form of effort points, are gained in addition to bonuses gained by increasing level. A Pokémon which increases in level using a EVs, making it weaker than a Pokémon who increases in level normally. Roughly speaking, defeating fast Pokémon increases Speed better than fighting slow Pokémon, defeating Pokémon with high hit points improves HP more than defeating Pokémon with low HP, and so on. For example, fighting 100 stat more than fighting 100 Abra of the same level, whereas the Abra will improve the Special Attack stat more. In more. In Generation I and Generation II effort points given are equal to the Pokémon's base stats.