After May 31st if you try to issue a miles ticket you will noticed that they will charge more miles to what it looks like to be a tier selection rate. I just confirm with the Social Media Team that these changes will be announced tomorrow morning! I was trying to issue a ticket to my parents going back to Brazil when I realized they were charging new values. It was frustrating since they already changed the system and did not let us know so we could get ready for this. I guess I'll just have to pay more for my parent's flight!