EV Training My Mewtwo

So, with the help of a lot of you guys I finished EV training my first poke! Here is how I finished:

DEF 50
SPATT 252
SPDEF 50
SPEED 158

I did run into an issue though and I am having trouble figuring out where I messed up. I loaded up his SPATT before the others and he was gaining 15-16 points towards it every time he leveled up. Once I finished with his other EVs his gains began to look a lot more normal, as he was only gaining about 4 points towards SPATT at every level. I am still a noob with this stuff, and as I mentioned, this was my first go at it. Now that I have a better grasp on this EV system it should make it easier for me to understand what you guys have to say about it. Any help is much appreciated as usual!

Nice that you managed to learn some of this stuff. Well, even though Mewtwo is a ridiculously powerful Pokémon that can OHKO most in-game opponents, that's still an alright spread for it in-game.

Pendraflare said:

Nice that you managed to learn some of this stuff. Well, even though Mewtwo is a ridiculously powerful Pokémon that can OHKO most in-game opponents, that's still an alright spread for it in-game.

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OK, cool. I have two others that are level 100 but I did not EV train them. I guess I'll find out how much of a difference this makes when my fully EV trained Mewtwo hits level 100 as well. He is a neutral nature if that makes any difference at all. I was overjoyed when I saw the result of loading up his SPATT after his first couple of level ups, but kinda got that sick feeling in my stomach after I filled out the rest of his EVs and he was only gaining the "usual" amount in SPATT afterwards. I was really looking forward to say.....500 something SPATT. What is the disconnect here? I was thinking he would continue to gain 15ish points to SPATT after I finished off his EVs, but I feel like I maybe just balanced them all out by finishing them. Is this the case?