The $4000 Tuition & Fees Deduction (TFD) is only a deduction from income, before tax is calculated. For example, if you are in the 12% tax bracket, you save $480 ( 4000 x 12% = 480).
Or did you mean you used $4000 of expenses to claim the AOC credit. The AOC ia a maximum of $2500
The $2500 American opportunity credit (AOC) is a dollar for dollar reduction in tax. If you have less than $2500 in tax liability, you will only get up to $1000 of that as a refundable credit (direct refund).
