Sep 27, 2017 - 8:25 AM
Hi again Manikad21,
Sorry for the delay but it took some time to ask around. I finally received the confirmation from the SBB that people are only in title to receive a discount on the Regional-Pass Bernese Oberland if they validate their Swiss Travel Pass Flex for ALL days. So the days of both passes need to overlap. In reality this is not a viable option as it is too expensive to use two passes as once.
I hope train staff won't make a problem out of this for you, but just explain them that it has been sold to you this way and I guess it will be fine. Many travel companies apparently don't know this, and I can't blame them as it's pretty hard to figure out.
Enjoy your trip!