Styles of WCS differ, depending on where you are, or what kind of music you dance to. Texans do distinguish between Whip and Push. However, there is as much or more variation from teacher to teacher or studio to studio within one city as there is between the cities. Once again, this is a generalization and can not be considered a universal truth. Once again, this is a generalization.
Nothing is extra.
The man basically only moves his arm as much as is necessary to produce the lead - no more. The Push and Whip put more emphasis on complicated patterns, where WCS accents more footwork and body motion. All three terms, swing, shuffle, and jive, come from jazz music. They refer to the subdivision of the basic beat in two unequal parts. The fact that such a division can be viewed as two notes out of a triplet does not mean that the exact triplet division was the basis for this rhythm.