CP268 tells you we made changes to your return because we believe there is a miscalculation on your return. You get an overpayment credit when your tax payments exceed what you owe.You'll automatically receive a refund of the credit. Locate the closest Taxpayer Assistance Center to you. You received this notice because the deposits or payments applied to your account didn't agree with what you claimed on your federal tax return. This form is for general instructions that apply to all corporation tax forms. It includes a variety of topics about how to fill out your form. You can find the CP or LTR number on the right corner of the letter. You must submit a copy of the letter you sent the IRS to request the additional time to file. Several of our clients have received balance due notices when the return was filed and funds withdrawn electronically.