On the footer, both frames were formatted with the frame styles “Page number top” and “Page number bottom”.
Notice how the bottom frame has a small space below and after the numbers (the frame didn’t inherit its size from the style), but the top frame is correct as it was manually formatted to have its size to be as small as possible, so it does not have extra spacing.
You can verify the frame styles “Page number top” and “Page number bottom” have different sizes defined and try to modify and apply them to the frames containing the page numbers: They won’t change because the frames don’t inherit the sizes from the styles even if the styles are reapplied. Only the positioning (inside or outside) is modified if the style is reapplied on the frames.
Although it is possible to use a paragraph style to format the page numbers aligned to the right, that doesn’t work if the frame’s positioning is mirrored on even pages.
This difference makes the positioning wrong and reduces the styles’ usefulness, as on long text documents with many page styles it becomes harder to position items using styles (imagine having to manually position every frame on a text document comprised of 20 articles, which is not uncommon for scientific magazines or books).
2 | 2
1st line
2nd line
3rd line