I’m a stickler for reading posts in my feed in the order they were posted. In Metatext, arrows pointing up on the “Load More” bar indicate new posts will be added above the bar, and your focus will be at the bottom of this list of new posts, so the next post in chronological order.
If the arrows point down, your focus will be at the top of the list new posts, so you’d have to scroll down to see the posts you missed. Scroll the timeline down to make the arrows point up, scroll up to make the arrows point down.