Oh thank goodness, I almost had a heart attack for you!
"Eorzea...without Lucke? NOOOOOOOOOOOO!" <--- me as I read this thread
Oh oh oh...my code is also 18 characters long! Le Gasp! I pre-ordered from Gamestop (after originally pre-ordering from Amazon). So we just have to put them into some other thing-y and then we'll receive the 20-character code-y-wode-y?
Or is it possible that only the Japanese keys are 20-characters, and all else are 18, and this has just been a typo sent from the underworld?