An update, which further displays evidence that exposing the interior of the cutting promotes root growth.
Cutting 1 - horizontal cuts into the stem:
Cutting 2 - Straight cut:
You'll notice that the cutting I just cut the end straight off only has one root, compared to the multiple roots on the vertical cuts. Additionally, you'll see that where that one root started growing was from where the stem got ripped (where my cut wasn't so clean).