The client is updating OpenDNS directly without issue. Good work! Thanks for all your hard work on this.
The client does not appear to be sending the updates through DNS-O-Matic, but to OpenDNS directly. If Zeroshell were to update DNS-O-Matic, the one update message can propagated to DynDNS, OpenDNS, and other dynamic DNS services as well.
Here is the API documentation for DNS-O-Matic.
A single DNS-O-Matic client updater in Zeroshell effectively gives you a client for all these dynamic DNS services:
DNS Made Easy
DSL Reports Monitor