Two Xboxes with Open NAT

[#1]

Hello.  I have FIOS with the MI424WR-GEN2 router.  I am trying to get both of my xboxes to be able to access Xbox Live with Open NAT but, so far, all I get is one with Open and one with Moderate.  I've set up Port Forwarding (with the appropriate Live ports) on one and DMZ on the other.  I've also tried using Port triggering rather than port forwarding.

Any suggestions?  I guess it's not too big of an issue as we probably won't always be playing online at the same time.  More than likely, one will be streaming Netflix while the other plays online. 

Anyway, I would appreciate any tips as I'd love to achieve "Open" for both xboxes at the same time.

Thanks!

[#2]

I think I know an answer that will work.

#1 Stop forwarding / DMZ.

#2 Turn on UPnP in the router.

#3 Please report back the results.

[#3]

how do you turn on upnp in router? should i turn off nat for better gameplay on xbox?

[#4]

You do not want to shut off NAT. That will break your Internet connectivity. UPnP is turned on from within the Advanced section of your router. It's nothing more than a checkbox and save to enable it.