UPDATE: This could be intentional because this inconsistency can also be seen when crafting/"stonecutting" Cut Copper. This may also be because the stonecutter's purpose is to dim down on how many resources are used when making something for a smaller output, i.e. slabs and stairs.

Steps to Reproduce:
1. Craft Copper Grate
2. Obtain Copper Grate using the Stonecutter

Expected Results:
You should get 1 Copper Grate from Stonecutting a Copper Block
OR
You should get 16 Copper Grate from Crafting them instead of 4.

Observed Results:
You get 4 Grates from Crafting (4 Blocks -> 4 Grates)
You get 4 Grates (more value) from the Stonecutter (1 Block -> 4 Grates)