Originally Posted by
jsloan
The fare is priced in Euro but stored in NUC, which is "neutral unit of conversion" (but where 1 USD = 1 NUC, so I don't understand the point). So, it's possible that even though the price didn't change, the underlying fare (measured in NUC) did, and so therefore they're detecting a fare difference.
The neutral unit of construction (or currency) is a private currency where the exchange rates are only updated (by IATA) once a month. It's always equal to a dollar, but it may diverge from the dollar exchange rates of other currencies over the course of the month.