Does anyone know what the numbers are that print across the bottom of Form 1040-V when a client has a balance due?  Someone asked me & I can see the primary SS #, then 2 Alpha characters ??, then the first 4 letters of the primary last name, followed by a series of numbers.  This client is upset to think that the 2 Alpha characters do not match either of their names ... Clearly, it's something in the software, but I don't know what to tell them ...