What about the case where you're booked on the domestic leg of an international flight and the fare buckets are different? For example, look at today's BOS-ATL flight 443. For first class, it has fare buckets J/C/D/I/Z as it is marketed as the first half of BOS-ATL-BOG, even though a plane change is required in ATL and the BOS-ATL leg is just standard domestic first. The rest of the BOS-ATL flights have F/P/A/G fare classes for first class as they're just standard domestic flights. So if I booked a Z fare on BOS-ATL flight 443, what fare bucket would have to be open on flight 1801 (BOS-ATL, 1.25 hours before 443) for me to SDC to it?