If you want to be cynical, pick up a handbook on engine management from the Lycoming disti stand at the next GA exhibition. It basically says: we think you are all idiots so we want you to run engines well rich of peak because that way you can't damage them. It also says things like "our engines are built to the highest standards so there is no point in doing anything to make them vibrate less".
It is apparent that a lot of the instructions/procedures in GA have at best no justification; at worst they are dictated by lawyers.
To be fair, if you look at the standard of instruction when it comes to engine management in GA, Lycoming are stuck between a rock and a hard place... they do sort of say that if you have proper engine instrumentation then you can run LOP but they distance themselves from it as far as they can.
Deakin should be compulsory reading for everybody who has 3 levers, and all of them should have a multi cylinder engine monitor
