On my wish list since 1998:
 
How about a little button at the bottom of the SO-E  Release Sales Orders screen that says "Print A Packing Slip".
 
This would launch SO-C, enter only that sales order number in the from/thru, and print the Packer according to the previously mentioned Report Default Settings.  
 
Hopefully, the default settings would include number of copies, and graphical form name.

The packing slip makes a great deal of sense.  Point of Sale people would more likely enter the SO with a Released status and want to print the invoice from SO-A bypassing SO-E altogether.
 
Lynn Pantic