Good questions.
The a confusion comes from nomenclature - most consider the front wall as the wall you view while listening, but in this case they refer to it as the rear wall (rear of the speakers). If you look into their other guides that have diagrams you'll realize that they are referencing we is often called the front and side walls. I inputed for a monopole and got the same answers as for side/front walls as shown in their other guides.
Not to quibble, but the center to center spacing between speakers would be 5.82 ft. If you follow the other guides you'll realize that they also prescribe listening setup of an equilateral triangle between speakers and listener which produces classic near/mid-field listening setup.
I laid out my room using their classic Fibonacci ratios and started out using their recommended near/mid-field setup but have since deviated slightly. Even toe-in can make a difference, feel free to experiment. With my monopoles the near/mid-field setup provides wonderful intimate imaging that snaps into place in the defined listening position as opposed to typical "far-field" listening just seems like the sound is coming from "over there" in a disconnected remote place.
