The wave plate should be flat. Say it's concaved: this says the plates are worn out, the clutch center moves into the clutch outer: meaning, the frictions thin out and the wave plate goes from flat to almost concave. So no the clutch center does not move, but the plates move into the clutch out. Instead of the coiled springs, the wave acts like a spring. In other words, the more concaved, the more the wave trying to go flat, the less tension, the less throw, meaning, the concaved takes up the throw trying to break the plates apart.
Cheap fix is to shim it with a steel plate next to a steel plate: moving the wave plate flatter. The right fix is to change out the clutch pack with all new so the stack is back to said thickness, the wave plate shows it goes flat.
So it's a 1/4 turns out from a lightly seated start, turn the cable adjust so there is almost no slack at the lever's gap.
