We call it 3-Step as it is about: 1/ Cleanse, 2/Treatment, 3/ Moisturise & Oil These three steps need to be performed day & night for healthy and radiant skin. We added the Face Oil to the set, as the Face Oil can be used instead of the Moisturiser OR you can use it in combination of the Moisturiser. Hence it wouldn't be a separate step, but more about what kind of product texture you prefer. A lighter and nourishing one; then use the Moisturiser. A little heavier and nourishing one, then use the Face Oil. That's why to us, it is still a 3-Step, as we don't see the Moisturiser or Face Oil being used one after another but rather in combination when the skin requires more fatty acids / lipids in the form of a Face Oil.