I have never felt that having confidence is an issue :P

I have made numerous bookings using various offices and they have always defaulted to pricing in the currency of the office which has been issuing the ticket. When phoning US, always been USD, UK has always been GBP and Australia has been AUD

The booking fees have also always been based on the office called which is why I never pay for award bookings through the Australia office. The currency conversion fees are always significantly better than paying $60 for the Australia office to issue in AUD

That the OP paid in CHF does suggest to me that the ticketing was performed though the Swiss office. One thought that did spring to mind was whether the op asked for it to be charged in CHF or the agent offered it and so it was passed to the Swiss office for ticketing who then ( incorrectly possibly ) charged the CHF70 fee