This is quite an old plan from the days when my original drawings were never returned and there was no chance to preview the plans before they were published. This meant that mistakes and in a few cases deliberate alterations by the draughtsman employed at the time, could not be spotted before publication.
Things are much better now and the odd mistakes are usually (but not always I'll admit!) picked up and corrected before publication.
Still, with possible distortion during printing and poor storage (damp!) of paper plans, it is always (as the previous poster suggested) better to view them as guidance rather than something to blindly follow.
This also gives you the option of tailoring a design to suit your individual needs.
Glynn Guest