Renaming items costs as much as repairing said item.

As per version 1.8 i expected renaming items to cost 1 level

However, renaming an item with multiple (more than 1) nbt tags costs the same as trying to repair said item rather than just 1 level. Escalates based on enchantment quality. (may cost over 30 levels.)

1. Have an item ready to rename with multiple nbt tags.
2. Just try to rename it.