It is a printing error. I have just telephone the AE Flying Blue Gold Card line (wasn't that the best way to find out?) to say that I had "heard" that the number of miles was changing. The agent told me that that was not true, and then asked if the source of my information was a mailing that had been sent out. I replied that, although I had not received the mailing myself, that was indeed the source. He then confirmed that the mailing and contained a printing error and that the number of miles remains as at present.