I understand that there is only a 10% chance of Ominous Wind raising your stats, which should result in an activation within about 10 uses, statistically speaking (I know it's a chance, not an exact representation).
In my game I have a Decidueye with Ominous Wind. I have kept the move for it's stat boost and decent power (obviously). However, I have never (not even once) received a stat boost when using this move. I have even seen an opposing NPC use the move with success. I was curious, so I went on an "Ominous Wind Spree" where I used no one but Decidueye and nothing but Ominous Wind. I played for over an hour with not a single stat raise.
Has this ever happened to anyone else? Am I just 'that' unlucky?