If the device doesn't show up in the Obi dashboard then the problem isn't just the SIP port overlap.
The Obi devices default to using port 10,000 for management from the Obi dashboard. I ran into this in trying to get 2 devices to link to the dashboard from the same network (202 + 1032), I ended up finding a setting in the device admin pages that I changed and seemed to have fixed the problem.
What I did was go into the Obi202 management page (pick 1 of your 2) and go to the Voice Services --> OBiTalk Service --> LocalPort. Uncheck the box for defaults and change the port, I used 10010.
At that point you will need to reboot your router and both Obi devices, at that point both should show up as connected on the dashboard. This worked for me perfectly, I don't know if this resolved the issue or if it was just a magical coincidental.