Cheaper renaming when deleting default text

I've only tested this on a diamond pickaxe. There was 3 enchantments on it, unbreaking, efficiency, and fortune, (Pretty sure they where maxed out, but I can't open the game at the moment to check). When repairing it using 3 diamonds, it gave me a cost of 9. When deleting the default name until it was blank, I was able to repair it for 8. I don't know if this should happen or not, but since the name reverts back to the default when blank anyway, it didn't seem right to me.

My apologies if this is a duplicate, I did a quick search and didn't see anything the same after skimming through.