If you are getting a refund it does not matter - there is no penalty for filing a refund late. You just don't get the refund until they get the return. If you owe and are assessed a penalty then your PO receipt is proof of timely filing and the penalty will be abated. You wait for the penalty to be assessed and then challenge the penalty with the proof of mailing - you don't send the proof with your return.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
