My stove is supposedly 85% efficient. Not bad, right? I got to thinking... what are the efficiencies at low and medium burn rates? I have a CAB-50 and I just have low-medium-high control. The convection fan seems to take forever to come on. Fuel can be burning in the pot for as long as 10 minutes before the fan is engaged. That's a lot of wasted heat! Has anyone heard specifications on high vs. low burn, and efficiency?