Attempted again to get this working. Seems to work correctly now except you level to 5 instead of 4 at the end of the Nautiloid.
Version 1.1
Deprecated the optional file. After studying other XP mods I realized that I had a large misunderstanding with how XP requirements are implemented (I thought each number was the new threshold, not the total amount needed to get from the previous level to the next). The progression was rewritten to make the 1-4 fast level work as intended, and then follow NewScale's 1.5x math thereafter.
Version 1.0
Initial release. Sorry if you downloaded this version, it was wrong.