Yes, I can understand your skepticism. I'm not fully sure about the program either, but I am going to try it and see what happens.
As far as reaching cystic acne, I think the method with the ice cubes that the book recommends seems like a better, cheap alternative to other remedies... in the book, it explains that coldness on the skin reduces inflammation (which actually helps spread acne through constricting pores) by shrinking blood vessels, which lets BP get in and do it's work. Then, a short time later, the book explains that extra blood comes to the area to warm it up again, doing so gradually, and carrying with it extra white corpuscles with curative powers (blood's natural infection fighters)
Sounds like a good scientific explanation to me. The author does say though that "tractable" forms of acne (5% of people using the program) may require another step of some kind of retin-a (i didn't read much about that part in the book). Hopefully, sedulous, I, and any others trying the program will have success. I would recommend checking the book out at the library and just reading the couple of chapters with the science in them.. also the beginning is an interesting telling of how amazing skin really is!