If you owed 14,000 on the original return you probably had a estimated penalty on 1040 line 38. So line 16 on the amended return will be less than 14,000. Which I think means the 15,000 refund includes getting the penalty back.
IRS Instructions for line 16……
You are filing Form 1040-X to amend your tax return. You sent a check for $1,500 with your original return, reflecting a payment of $1,400 in taxes and a $100 estimated tax penalty. When completing Form 1040-X, enter $1,400 on line 16 (the check sent with the original return minus the $100 penalty).
Didn't you enter the W2 from your employer? Why didn't the withholding get entered? Did the employer send you a W2C to correct it? There may be other things missing from the W2 you originally entered.
