Steve,
The Power flour is a Pendleton Flour Mills (Seattle) product. I haven't personally tried it but I know that fellow member giotto has. He is a skilled and knowledgeable pizza maker who is constantly tinkering with his recipes and technique, and should be able to answer your questions based on his own experience with the flour. He has posted on his use of the flour starting at
http://www.pizzamaking.com/forum/index.php/topic,524.msg4966.html#msg4966.
I have a brochure on the Pendleton flours and the Power flour has 13.5% protein, 0.57 ash, 65% absorption, and comes in both bleached and unbleached versions. Using the guidelines from King Arthur, a flour with a protein content of 13.5% falls within a range (13-13.7%) considered to be "medium high gluten". KASL, King Arthur's high-gluten flour, is at 14.2% (which falls in a range of 13.8-14.2 considered to be "premium high gluten").
Peter
