I would like to buy a ticket from Zug->Zürich (train stops in Baar), and I have a Zug all zone travelcard inserted to the mobile app. When selecting ticket options, I have an option for ZVV Extension ticket (4,4CHF with Halbtax), or the other option for 7 zones (8,7CHF with Halbtax).
If I buy the extension ticket, will it be really valid?
An other question, if I try to buy a return ticket after 9, then I got 2 extra option beside normal (which is 17.40CHF). First is "ZVV 9-o'clock day pass" for 13CHF, or "ZVV Extension day pass" for 8,8CHF.