Okay, new issue. When I use the right slot of the Macerator for additive maceration, it only uses up one item. For example, I place a stack of Iron Ore in the left slot and a stack of coal in the right slot. It gave me two stacks of the dust that you cook into refined iron, but only used up one of my coal and only took the coal from me when I took the stack of coal out. I tried it again by using two stacks of iron ore and a single piece of coal and was able to get 4 stacks of refined dusts without using up the coal as long as I didn't try to take the coal out. On the other hand, though, when I put in Tin ore and Copper ore, it worked perfectly fine and took 1 tin ore for every 3 copper ore to make bronze dusts.
Not sure if that's intended or a bug, but thought I'd let you know.