The bonuses to attack for special bloomers currently stack additively and not multiplicatively when being held by Ichirin, Flandre, or anything else that has Pure Power or Hustle. A few of us noticed this and realized that in formats such as Little Cup, CIchirin actually misses out on 7 extra attack, which is, frankly, a huge deal. This also allows Choiced Attack Flandre to hit a whopping 1084 attack stat when it has a +attack nature. So there's definitely a noticeable difference when it comes to these 'mons and special bloomers.
Apparently it's just the display that's incorrect; the damage is supposedly accurate according to Iris.