There lies your problem. Your definition of a pendulum stroke encompasses strokes that most would not define as a pendulum stroke. When most people refer to a pendulum stroke, they are referring to a pinned elbow stroke before and after contact. Widening the definition of pendulum stroke to suit your needs doesn't help support what most people refer to as a pendulum stroke.
You say most people. Well, since the pendulum stroke came from the instructors, and they teach some leeway with it, including dropping the elbow some after contact,(about an arms width), just where are these people getting there information from?