LOL, ok, so I just finished RNGing the Scyther for nature/ability/gender and such, but when I hatched the egg, it WAS shiny (And I didn't want it to be shiny). I entered this combination for my ID/SID:
25515/13000
And my real combination is:
25514/13000
So was I supposed to really change like, everything? I thought the slightest change would make it not shiny. But, it's ok, I'll keep it. Lots of people like Shiny's, so why not? :]
It's the way the shininess is determined. The end result has to add up to less than 8 for it to work. (or something like that) Anyway, that would be enough of a difference for some PIDs and not for others. I recommend changing both and by more.