It has a lot with how soon one will be turning down the fire and where the air control are set to. If the stove is being asked to heat a cold barn up 20º one MAY CHOOSE to push it a lot harder than if one is raising the temp 3-5º in a well insulated house.
Sure, but that has nothing to do with what the stove is capable for burn time. In order to get the stove to burn for as long as possible you reduce the burn rate as much as possible and get what you get for heat. As a stove performance specification, envelope demand is irrelevant. The stove could be outside and still have the same burntimes.