Grrr...
The only problem w/ that is that you might accidentally get a "2EVer" (Seaking as opposed to Goldeen) - and forget to count it.
When you're doing, say, a 252, I tend to do 10 vitamins - because you know you're not gonna get that wrong. Then you fight 15 1-EVers w/ the pokerus/power item (giving you 150) - if you fight ONE 2ever (Seaking, Muk, etc), then you have 152, and don't need to do anything else. Otherwise, you do 1 more 1Ever w/o the power item, getting 2 EVs.
Since most sets are 252/252/4, you do this twice, then get 4Evs (2 battles w/ a 1Ever w/o a power item, but w/ pokerus).
This way you always have the left over 2 EVs - the test, then, is to check and see if 2 EVs will make it have the ribbon. If you get the ribbon early, you messed up; if you don't get it after the graveler/whatever, you messed up.
The way you do it, you never know if you're wrong - which means I have to go and double-check the guys you EVed for me. - yeah... math :(