Hi Robert,
Because the DN's are set up as dual-line you need to add the following (huntstop channel command). Have a look;
The following example creates an ephone-dn with the number 103 in dual-line mode. The no huntstop command allows calls to continue to hunt to other ephone-dns if this one is busy or does not answer. The huntstop channel command disables call hunting to the second channel of this ephone-dn if the first channel is busy or does not answer.
Router(config)# ephone-dn 10 dual-line
Router(config-ephone-dn)# number 103
Router(config-ephone-dn)# no huntstop
Router(config-ephone-dn)# huntstop channel
Router(config-ephone-dn)# exit
From this CME doc;
http://www.cisco.com/en/US/products/sw/voicesw/ps4625/products_command_reference_chapter09186a0080611350.html#wp1056194
Hope this helps!
Rob