I'm not sure what's going on with my codes. I got the early access code which I assume was the 18 digit code, but it tells me that the 20 digit code that I also got (which I assume was the actual preorder code) was already redeemed, but on Mog Station it tells me that I only have Early Access but not continued access into the full expansion. Then again, the 18 digit code did lead to the 20 digit code too.

If I had to guess, I probably already redeemed everything when I first got them back in Feburary and don't remember all the exact details. If it counts, I also ordered directly from the SE store.