I have read that when using a saute pan one should heat the pan empty, then add the oil, and then the food imeaditely afterwads. The idea is to not expose the oil to more heat history than necessary so that it doesn't change flavor. Ok, makes sense to me. But then I read the owners manual for the new saute pan I purchased and it states one should add the oil, butter, etc. to a cold pan. I'm guessing this is to avoid overheating an empty pan. So which method is correct, heat then oil or oil then heat?