I've always been intrigued how the whims of a CP, in so many different airlines, that makes it gospel. They can't all be correct. Why don't people operate the equipment the way it was designed? However, Boeing have changed many things over the years after feed-back from operators. They do the job day in day out in a spectrum of circumstances. SOP's should be a living thing, but still it is often the whims, without too much rhyme or reason, that make a mess of it. Oh for the simple life.