Richard, Got it. Thanks for running that down.
So, the BIRD does control the isolator Relay for chassis to house charging. For house to chassis charging, the only function of the BIRD is to activate the "lockout relay" if/when the generator is running.
The detail you provided was helpful in understanding, what appeared to be redundancy, at first pass. I'm not generally a fan of diode isolators, as you may have detected in my criticism of the Lambert Maintainer, but I think it may be a very good and reliable choice in your configuration.
I've seen BIRD installations where the float voltage of 13.2v, from the converter/charger, was not enough to trigger the BIRD to close the isolator, and the result was NO charge voltage sent to maintain the chassis battery. Your installation avoids that possibility and the perception of a failure.
Thanks again, for taking the time to explain.
'97 Bounder 34V, F53 7.5L-460