I don't mind having an argument with the lounge reception agents but I'm not sure there is much evidence I can present to convince them. I checked another "real" Flagship First ticket I had booked before (which btw, is only around 100 dollars more expensive than this one, so don't tell me I'm not paying enough for Flagship First), and found no difference on how they address the class of service other than the Booking Code. Otherwise I can only show them the screenshots attached in this post...