User blog comment:Purebreaker/Nilana, The Spirit Seeker/@comment-7709681-20130906155035/@comment-16210885-20130907083619

I think the "bonus ap" is just Purebreakers "mistake". Since she probably copied the descriptions of Spiritual Fire from Ahri, that is the reason why Spiritual Fire is the only one with "regular" AP.

Basically, the "bonus" is an error of Purebreaker...