He is not a leading wyckoff expert, that would be David Weis now that Tom Williams is gone, followed by Dr. Gary Dayton.
Feibel is just a system/course seller. You know those guys who read other people´s books and courses, then "create their own" courses? They just give a slight different name. That is what Feibel does, do not sweat about his stuff, he sells free knowledge in an expensive packaging, that is all. All "his" stuff you find in the book "Master the Markets" by Tom Williams, which is from where he copied mostly everything, the rest he copied from Dr. Gary Dayton. For example, this EHP you wanted is the Deep Practice he copied from Dr. Gary.