After you file

Did you have a penalty on line 38?   it's not for filing or paying late.  It doesn't have to do with last year's tax return or not paying estimates for this year.  The penalty is an "estimated" amount.    It's a penalty if you owe too much or for not paying in enough withholding during the year or not paying in evenly.  It's common for the IRS to adjust the amount of penalty.