Hello andrew and cdnart,
Xerox does not post drivers or firmware that is not fully tested on Xerox.com. This is why you were directed to call in to support for these releases. Please contact support at 800-821-2797 and ask to speak with a 2nd level to discuss your issue.
In the firmware mentioned 4.9.14, there are some slight improvements to smaller pdf creation from the printer but, the speed increase is not dramatic and, we are still limited by the printers processor speed when compressing the data. The workaround would be to use the Xerox scan utility.