That's a display error, not a math error. You don't need 26% Haste to cap it, but 25%. Only gear doesn't display it correctly.
Of course it would, because players make mistakes or don't fully understand the game dynamics and don't know any better. This could well be one of those examples.
This is not how it works, there are no numbers at all involved. if(mob.isRedStaggered()) { dropTheDamnKI(); }

