Hello Negotiator
You can answer the question by yourself. Please kindly look up the validity map:
https://www.sbb.ch/en/tickets-offers/travelcards/area-validity-map.html
The SDP is valid from Täsch to Zermatt.
The SDP is not valid from Wengen/Grindelwald to Kleine Scheidegg.
As a rule of thumb (with a very few exceptions), the SDP is valid to inhabited places where people live on 365 days / year yet not beyond these points.
Kind regards,
Roland