I've noticed this before, and don't understand this. I trained this Roserade, with these Evs I want: 252 SpAtt, 252 Speed, 6 Hp.
Ok, normally I start off with speed. I battle the guy outside Eterna City, with the 6 Magikarps. I have PoKeRus and my Roserade, along with a Power Anklet. So, if I battle the guy 4 times, that would equal 240 Speed Evs (Magikarp Evs(1)+Power Anklet(4)xPokeRus=10)(that means 60 Speed every time) right? That means if I battle him one more time, without the power anklet, I should receive 12 more Speed evs (Magikarp Evs:1xPokeRus=2x6=12) right? That equals 252 Speed Evs total.
Next I would do the SpAtt. I battle Gastly in the creepy house thing in Eterna Forest. I have PokeRus and Power Lens. I battle 25 Gastly, that should put me at 250 SpAtt Evs(Gastly Evs:1+Power Lens(4)xPokeRus=10) right? Next I take off the Power Lens and battle 1 more Gastly, which puts me at 252 SpAt(Gastly Evs:1xPokerus=2).
To finish it off, I battle Bidoof 3 times with just PokeRus which should put me at 6 Hp Evs(Bidoof Evs:1xPokeRus=2x3=6) right? Which equals 510 Evs(252+252+6) right?
Then I check to make sure to see if I still have PokeRus, I do, but I still don't have the effort ribbon. I don't understand this. My math should be correct. Unless PoKeRus and Power Items don't give off 10 Evs for battling a 1 Ev Pokemon. What I'm I doing wrong?