I have created a Charcoal block to add to my mod pack and have made the recipes to create it out of 9 charcoal. I also it possible to undo the block via the crafting table.
However I set it up that when you break the block it should drop 6 charcoal. And all it does is drop coal.
So to make sure this was a bug I checked a similar thing which a a mossy stone wall it uses the same coding example COAL or COAL#1 and Cobblestone_wall#1
But both of these will revert and drop only the COAL or WALL...
I am sorry to say the MCreator has a bug when it comes to these types of drops via blocks