I saw the thread regarding acknowledgements not printing correctly so I thought perhaps the same answer would remedy my invoice problem, but no dice.  The program name for SO-F is set to t6sof.run but they are still printing wrong...
 
Also, if I go to SO-F, choose reprint invoice, do a lookup for an invoice number, highlite the appropriate invoice and press enter the invoice field is populated with 10400 instead of the invoice number...

What exactly is not printing correctly?  Need a better description of the problem.