I guess it might come down to experimentation, but is there any reason why, if pellets are burning thoroughly and cleanly at the '3' setting, that I would want to bump it up to '4'? I know that it's not desirable to have any unburned pellets dropping into the ash pan, but I'm running Hamer's and they look to be burning well, although down pretty close to the auger, with nearly all the air holes visible in the burn plate. So, if the stove is working at a 3 setting, why would I want to go to 4 or higher?