Answer "Yes" and the amount you enter is the ~13k (~18K - 5250) from box 14. The net result is that the ~$13K (the amount included as income on your W-2) is used to calculate the LLC (Lifetime Earning Credit).
If you got more than $5250, the amount above $5250 is usually already included in box 1 of your w-2. Since you have paid tax on that part, it is considered your after tax money and that amount can be used to claim the tuition credit.
