I figured out the problem with the dynamic DNS setting, at least mine, which used to flawlessly update my IP if it changed via DNS-O-Matic to OpenDNS.
The settings were absolutely correct. The problem was what is called a "Double NAT" situation, which I unintentionally created when I was trying to resolve the Secure Spot disaster. When I got so frustrated that I re-set my entire network, hard-resetting both the DIR-655 and my DSL modem (Westell WireSpeed 6100 Dual Connect), I forgot to put the DSL modem back into "Bridge Mode" to avoid this double NAT problem. Once I did that, DNS-O-Matic once again began to automatically update my IP to OpenDNS via the DIR-655 and all is well once again.
FYI. Hope this helps anyone else.