Has anyone had success booking a EC seat at the discounted rate on a KLM code share? For example, I am coming back from AMS to JFK this weekend on a 747 and wanted to book an EC seat at the 50% discount (I'm GM so ST E+), however I am getting a bunch of different answers from the Medallion line stating "you are on a DL code share and unfortunately need to be on a KL marketted ticket with a different fare class" or "Golds are not eligible for the 50% discount because they are not ST E+, only PM/DM" etc.

Do you think I will have better luck at the airport or if I really want it, just fork out the 80 EUR instead of 40?