Problem With Anvil Config

[TheMysteriousN]

Describe the bug
Any integer below .5 auto-sets the cost to 75% of the total instead of the respective number in the config file.

To Reproduce
Set the config for the Anvil cost to .2, as that was what we tested with, then get a really any book and item (I used a prot 4 depthstrider 3)
Expected behavior
The cost will go from 11 -> 8 (75% reduction) with the anvil instead of the expected 2 (80% reduction)

Screenshots