Hi Michael,
Thanks for your continuing help. By moving the ISY/PLM next to the switches I was finally able to get both switches to restore so it must be some sort of real communication issue. I don't know what type of communication issue and I don't really know what else I can do. I have dual band switches and access points sprinkled throughout my house. I have FilterLincs on my equipment and UPSs. I have a SignalLinc for the dwindling number of X10 devices.
I'll keep tweaking, but I'm sure you know that this is the most frustrating part of Insteon. With X10 you could at least get a signal detector and send out a P1 and get some feedback. With Insteon I feel like I'm working a "let's try this" or even worse, "take my money, this might work" style of debugging.
Oh well, enough bitching. Thanks for your help!