Wait. So banked means in the system on the website, right? Then applied means actually applied to the gamertag.
So we have until 3/31/13 to use all the double xp?
Edit: I found this.
The maximum amount of XP Matches for any Gamer ID/Gamer tag during the Promotion Period is 200 Matches. XP Matches must be transferred to a Gamer ID/Gamer tag no later than 3/31/13 or they will be forfeited. If no Gamer ID/Gamer tag has been entered during the Promotional Period, all XP Matches will be forfeited.