And I never used the anvil to make single plates. Just cast metal into molds. That’s efficient. If there is a mold for something, better use it.
You cast ingots, then you double it on the anvil, then you heat up your boilers for rolling mill, and all of these is to produce a few double plates. Why not simply cast plates and double it on the anvil? I have no rolling mill, because I don’t see any usage for it in early game.