Years ago I was an efile tester for H&R Block's efile program 'TaxCut'...(disliked it for two reasons, because it was really just testing entries to match expected output and I had to be there at 8am...did it for one autumn only.) 

To the best of my knowledge, how software works in general, the data is translated and the line#s (fields) have alphanumerical output. Let's say field 4 is the last name and field 5 a number representing the characters in the last name.  Field 1688 might show the taxable portion of social security, and so on.  When a new form is issued, the software programmers have to um, program the..um software to match the database of fields that the IRS wants in its software.  Every software company goes through this testing process before getting IRS approval to efile and releasing its product.  ProSeries seems to be having a problem getting this particular form correctly programmed.  Maybe there's only one guy doing it now after his morning shift at Dunkin' Donuts?

(oh yeah, I wanted to help make this thread the longest thread the Community will talk about for years!)