After you file

The most likely outcomes of not filing by the deadline---you just abandon the account and the return and do not pay anything, since you pay just before filing,

 

Or...you miss the deadline for the discount and pay full fee for the Full Service--at whatever rate is in effect at the time that you finally file.

**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**