Enchantment Cost Fluctuate for same tools combining

Description:

I was having two enchanted rods both having low durability:

• 1st rod having enchantment: Unbreaking 3, Lure 3
• 2nd rod having enchantment: Lure 2, Mending 1

When I Combine them in Anvil, putting First rod and Second rod in First and Second slot of Anvil respectively, I get a Rod having enchantment Unbreaking 3, Lure 3, Mending 1 and costs me 6 lvl.

Now When I put First rod in Second slot and Second rod in First slot of Anvil, I get a Rod having same enchantment Unbreaking 3, Lure 3, Mending 1 but now costing me 12 lvl.

It can be seen in the Screenshot Provided.

Steps to Reproduce:

1. Make First rod having enchantment Unbreaking 3, Lure 3 and Second rod having enchantment Lure 2, Mending 1.
2. Try Combining First rod with Second rod in Anvil and see Enchantment cost.
3. Now Exchange their Anvil slots and see Enchantment cost.

Observed Behavior:

Both produce the Same type of Enchanted rod but their costs are different.

Expected Behaviour:

Both produce the Same type of Enchanted rod with same cost.