Originally Posted by
Stranger
If the entire itinerary is in Y, sure. But even then, price might have changed. If that leg is, for instance, part of an itinerary in P, for which there was no P available at the time of reservation, rhen it's a different story.
AC9101 (OP's flight) is FRA-YVR under LH492, that's why I was confident it's a TATL full Y fare as it is the most significant segment determining the fare.
The only thing that could have potentially complicated the matter is if this is a part of a return ticket with the other half in a more restrictive fare class.