Originally posted by megapoo
Got me locked out from entering codes for 24 hours.
What I'm guessing you could do is the same thing, on two different computers or web browsers with a different account on each one. You could still assign the codes to the same gamertag, but this is only a theory.
After one try it locked you out ? It worked for me a few minutes before I posted it so I could confirm it worked. I opened 2 Windows and lined up the apply buttons next to each other and hit then as fast as I could. Received xp for a 1hr 30 min code twice..