The current Danish grading scale was intended to make the Danish grades compare to the 7 category European ECTS scale. Despite the existence of the ECTS scale, many countries maintained their grading practices, using more detailed scales as the ECTS scale has not enough levels to distinguish the achieved level of proficiency. The ECTS scale was intended to create a framework to be used to effectively "translate" and "transcript" a grade from one institution/country to another.
I never understood that the current Danish grading scale was created on this apparent misunderstanding. Of course the ECTS scale had to have some fewer categories to condense the variety of more detailed scaling systems in order to make them comparable at the "transcript" level.
Even though the old Danish scale with the 13 seems to be numerically a little odd. It was probably intended to make the distinction between 11 and 13 in such a way that 13 really is something outstanding. It clearly shows the problem with the current 7 category scale. A grade of 12 means semantically “outstanding performance with only minor errors”. This may be fine when making the "transcript", but cannot make the distinction between “outstanding” and “outstanding with only minor errors”. The devil is namely in the detail.
I fully agree in creating a more detailed Danish gradin scale again. The 10 category scale formerly used in Denmark and currently in the US seems pretty fine. I hope though for an outstanding expert committee to take the lead on this.