As the fire gets lower, down to coals, is opening the air control more the proper way to go? I'm not talking about necessarily burning down the coals, though that is a factor for sure. This assuming one is hanging around near the stove and can fiddle with it. Is there a downside with opening it, like, all the way, when down to coals? I can see maybe losing more air up the stack or something, but I'm currently not seeing any downside to opening it up.