score:5
There are no Hungarian trains from Gmunden to Salzburg. All trains from Gmunden are operated by Austrian companies.
The old timetable is ELVIRA, correct? It shows the Austrian ΓBB REX trains as Sz trains. Example
There are direct trains from Budapest Keleti to Salzburg and MAV would sell tickets for those. However, the terms of use for MAV Start Europa tickets contain the following condition:
Train boundary: to border-crossing trains*