The term focal plane is a reference to correction. Normalized correction is one focal plane. Differentials correction is another. Night driving correction (full correction) would be still another. And finally no correction would also be considered a focal plane.
EndMyopia does not recommend any additional focal planes beyond those mentioned above, including multifocal lenses such as bifocal and progressive. Too many focal planes confuse your visual cortex and may result in undesirable visual issues. Additionally too frequently altering your focal plane may also result in visual complications, most commonly double vision. For best results follow EndMyopia protocol concerning focal plane use.