I know it's been ask before...but when we speak of burn times, is that the length of time a fire is burning? or how long we keep hot coals in box? the homestead claims 8 hour burn time, 12 hour of heat. wondering where I stand on my "actual" burn time. I can have enough hot coals in the morning to restart a fire, if I load her up heavy at night. So is this a 8 hour burn?