That's a good point, Eddie. Engines and the laws of physics know when an aircraft is engaged in private operations versus commercial operations, and change accordingly.
Captjns: Most of those great manuals 'allow', and some and even 'recommend', setting EGT to 50 degrees F on the rich side of peak in the cruise. Aside from the fact that a single point EGT gauge leaves you blissfully ignorant of where on the lean curve each cylinder happens to be, 50 degrees F on the rich side of peak is just about the
worst place to set mixture if you want to avoid exposing the cylinders to unnecessarily high pressures and temperatures. The laws of physics and chemistry, backed by data from millions of hours of operation,
prove it. As I said earlier and now for the last time in this thread:
The fact that the engine might survive the abuse or inefficient operation proves nothing, other than that many engines are manufactured with wide tolerances for abuse and inefficient operation.
A comparison between the condition and costs of running engines the blissful ignorance way, on the one hand, and the condition and costs of running engines on the basis of the science and data used by APS, on the other, is quite instructive. But only for those who are willing and able to learn.