Surpassing chance to fire an additional Projectile - 50 or 1 % ?

In the Patch notes i found the Entry:

"

Gemini Bow now has 1.15 Attacks per second (Previously 1.1), now has the implicit: +50% Surpassing chance to fire an additional Projectile (Previously Bow Attacks fire an additional arrow).

But my Gemini Bow ,which i used in the previous League ,(and many other Bows) only has 1% Surpassing chance to fire an additional Projectile

Is that a bug or a feature ;) Thc for any information