I don't know about that specific one but elections with complicated rules and multiple votes (where you can "kumulieren" and "panaschieren") are usually counted

I don't know about that specific one but elections with complicated rules and multiple votes (where you can "kumulieren" and "panaschieren") are usually counted with the help of software where the election officers manually enter every ballot into the computer after inspecting it visually and have to trust that the displayed end result is correct (although there are some manual consistency checks).