So, the boil off rate as a percentage or gallons/hr should be the same whether you are doing a 5, 10 or 15 gallon batch in a 20 gallon kettle? That seems to mean that if I am getting 8% boil off at X% PID power for 15 gallons that I could use X/3% power for 5 gallons or X*2/3 for 10 gallons to...