herpderp,
If the forwarding path for 1960 goes to a path that ends up with the other extension you want then you founnd out how it works.
If you want to do the same thing, but opposite of what it is doing now then you just need to create a new Forwarding Path for the other extension to use that goes to 1960 and then point the DID to the other extension. I am not sure I would change the existing ones unless I knew no other phone was using those System Forwarding Paths.
I am not sure what you are asking when you want to put it in DND, but here is my response to that.
If you put 1960 in DND right now and the System Forwarding is turned on for Station - DND on that phone then yes it will go to the other phone right away. However, 1960 will never receive any calls at all after that, even ones you want them to.
You can press F1 on any page you have questions about, and it will send you to the Help for that page.
Thanks,
TE