There wasn't any master plan. Each school did its own thing, depending on the commitment of their teachers (or the lack thereof).
Our school in Rendsburg/S-H got a few (5?) Sharp MZ-80K in 1981?, one MZ-80A a bit later (which featured an actually usable keyboard!) for programming in BASIC and Pascal.
The MZs were followed by two Commodore PC-10 around 1985 that were mainly used in the science departments.