Originally Posted by
fastflyer
Also not valid for domestic J to F upgrades (mileage upgrades and SWUs only for these).
This is incorrect -- BXP1s have always been, and still are, good to upgrade any paid J fare (domestic or international) to F. Works on J, R, D, I, whatever. I routinely use BXP1s for LAX-JFK to get Flagship Dining. It is the optimal use of a BXP1 in my opinion.