All the fletching items use carpentry skill but many have penalties applied to the skill, up to 50%.
So a high carpentry skill is the main determining factor for creating the components and the arrows, it could be the penalties are set to prevent grinding your skill by making a few dozen arrows, the reason is not documented in the mod. Making less than decent arrowheads and shafts is easy to do and making arrows from poor quality parts is going to give a lot of poor arrows, but even curved arrows will help improve your bow skill.