I've bought a Swiss Half-Fare Card. But whenever I'm buying a single-journey ticket, a Saver Day Pass or Day Pass for 2 on the SBB website, only Half-Fare travelcard is listed as a discount option. Apparently in the case of single-journey ticket, Swiss Half-Fare Card is available. But as to Saver Day Pass or Day Pass for 2, or trains from, say, Interlaken to Salzburg, it's really hard to tell whether a Swiss Half-Fare Card is still available. So, on SBB website, where are both cards acceptable, and where is only Half-Fare travelcard acceptable? Can anyone help me? Many thanks!