I agree with the general tone of the above but it does leave one a bit confused/doubtful when we are told, from one day to the next, “the way we have done it all these years is wrong. From now on, do it this way”.
Who is to say that this new officially-sanctioned method won’t be superseded in time? Perhaps it might be wiser to hang on to a few basic principles and keep in mind that the atmosphere and the aircraft haven’t read the manuals, nor are they concerned with any revisions to them.