Renaming spears costs more than 1 level using the anvil

In my survival world I tried renaming a diamond spear with Sharpness 5 and unbreaking 3, and it costed 16 levels. To my knowledge, renaming any item should always cost 1 level. I believe it costed 16 levels due to it having enchantments, as the more enchants you have the more it costs to do stuff with that item, however this shouldn’t affect naming.