it's adding up, page-21

Ben the 10-15 multiplication comes about from putting in a horizontal well leg 1500 meters long and having multiple fracs along this length. giving you exposure to a greater area of pay zone. so for example if you get xyz from one 50meter zone, what will you get from a 1500 meter zone with say 15 fracs along this length.

How and where they frac this horizontal depends on the geology and how and in what direction the shale fracs.
If you search around the internet you will find that some shales only frac in an upward fashion,some down some sideways. hope this answers a few of your questions.