Back when I was doing my NS - there were ranks like corporal
first class and private first class. For combat units, these ranks
were given for the different roles the men play in the section,
platoon or company.
For example - section commander for the 84mm section was a corporal
first class. 2 IC was a corporal, gunners were lance corporals and
loaders were PFCs. MG gunners were lance corporal and loaders were
PFCs.
Same with the platoons, section commanders were corporals, section
2 IC were lance corporals, and some group ICs were PFCs. These
ranks are more or less fixed all the way until the men finished
their reservist cycles. Promotion during reservist is when there
were vacancies to be filled.
That was before nearly everyone in charge of something was made
some sort of sergent these days. With NS being 2 years for everyone
now - rank should be given to those who can perform, not by
education level at the point of conscription alone.