As you craft things, you get better at crafting them
Small changes concerning balance, gameplay, or graphics.
Furnaces, assembling machines, production chains.
productivity increases when only normal items are crafted, if any quality recipe is crafter the productivity doesnt go up as if the item didnt count
This is on my radar now. I've been trying to figure out a way to handle this. I'll do some more research, but I'm out of town for work until next weekend. Thank you for the heads up!