Something Interesting about Archetypes

If there is supposedly 15 spell changes per class, and 3 archetypes, those numbers don't add up. we can assume each spell is changed for an archetype, but that still leaves one more upgrade. Would that be a change to the melee such as the tri shot archer in the trailer? or something else?

EDIT: oh man i love ADHD and ignoring obvious answers

 

It says there are 15 total archetypes, not spell changes. 3 archetypes per class for 5 classes is 15 archetypes.