Originally Posted by xONEx rules
When travel originates in a country for which a specific local currency fares is published and the ticket is sold in another country, the fare will be that published for the country of origin converted to the currency of the country of sale at the bank selling rate. The resultant fare must not be lower than from the country of sale.
Exception: Not applicable for sales made and/or travel originating in Canada or the European Common Aviation Area (ECAA).
The last sentence above makes it clear that even though Switzerland is not part of ECAA, ticketing through UK (for example) can be done at the ex-Switzerland price even if lower than ex-UK price. If the ex-UK price is lower it does not apply for xONEx starting somewhere else that has a higher fare.
Fare at origin country applies, except in the following circumstances
a) fare at sale country is higher AND sale country is not Canada or member of ECAA
If sale country has lower fare than origin country, even for Canada or ECAA, you cannot use it to start somewhere else.