CC Scale Wipe is backbone of the whole effect. It stretches the layer in a way we tell it to. To make the effect stronger, simply duplicate the layer once.
This expression positions Center property (the one that controls, where the stretch happens), just below top/bottom portion of the Text layer. Since source composition is “locked” in the center, whole effect starts from the center. We are using sourceRectAtTime expression to get value to streatch, even if the text is moving / animating.
As you can see, expressions are identical, just the final calculation is different – one positions Center at the top, other at the bottom.