Due, true, 0 degrees, and 90 degrees are all semantics. Every deed description can be interpretted or misinterpretted. What reall counts is the analysis, the intent, and what evidence exists on the ground.
I think that most clients don't understand or even read their deed. It certainly doesn't help that lawyers take archaic language to the extreme when writing deeds in the fist place. And most people will use phrases like 'true north' without making a distinction as to whether or not it is correct or even knowing the difference.
I had a project that was a determination of the shape of a town common. Descriptions spanned the time of the New England colonies to the present day. In many of the ancient deeds directions were referenced to cardinal directions along with some bearings in degrees and minutes. It turned out that many of the deeds had been surveyed and the surveyors attempted to construct the parcels surrounding the common in a grid like fashion with north being a compass bearing.
Since the town had changed little over time, and being a land mark historic place, much physical evidence existed , and could be surveyed to show exactly what north meant in the deeds. In fact, a map found in the archives of our state even showed the variation to astronomic north. The map showed the town common.
So I think it is better to have evidence than to rely on some book that purports to know the correct way to write a descrption. Unless, of course, everyone has read the same book, and abides.
Historic boundaries and conservation efforts.