Section 10 of the technical rule sheet for the xONEx fares states:

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 when BOTH travel originates and sales are made within the European Common Aviation Area (ECAA)/Switzerland.

I have seen several posts discussing taking advantage of this "Canadian exception" of purchasing a RTW ticket in Canada when the country of origin is somewhere with cheap xONEx fares.

My question is whether the opposite is also possible: can one purchase an xONEx ticket in the UK, with Canada as the country of origin, and pay the lower UK fare rather than the higher Canadian fare?

The wording from the technical rule sheet seems to allow this ("...or travel originating in Canada"), but it's possible that I am misinterpreting the rules.