XDJ AZ Feature Removal

Why does the XDJ-XZ allow a prolink connection for adding two CDJs on the outside  creating a 4 deck configuration and the XDJ-AZ does not?  There is a LAN port on the unit.  I don't understand why the feature would have been removed when the XZ was upgraded.  

Now a user has to toggle the AZ for deck control of 3&4 instead of just putting two additional decks on the outside. Making it impossible to do advanced layering in performances quickly.