I believe that, despite the fact that they share the same description & AP cost, they don't have the same effect.
The heal that you can learn with the book is twice as powerfull as the starting "heal" (mage & cleric archetype)
I'm not so sure. The tooltips that were given on the skill icon suggested that they were the same exact thing, doing the same amount of healing. I might be wrong in the fact that the tooltips don't actually display correct data.
