> A plumber would be a prime example of the vocation which is using this kind of system. > people finish secondary education at an earlier age then in the US (16 or even 15 in some cases), then they transfer into tertiary education in a fachschule.

Who the fuck know what they want to do for the rest of their lives at 15 or 16, most likely without having the possibility to re-invest 3+ years to change branch ?