Why three varieties matters more than it sounds
A learner trained entirely on German textbooks written in Germany meets Austrian administrative vocabulary, Swiss press style and regional word choices for the first time under exam conditions. None of it is exotic, but unfamiliarity costs seconds per sentence, and the paper is testing both the overall message and individual detail across four tasks.
ÖSD publishes the task count and the duration but not the item count or the text lengths; the official Modellsatz is the reference for those. This page prints what is published, with its source, and says "not published" for the rest rather than filling the gap with a plausible number.