Insteon unreliability with simultaneous switch presses

[Eric <eric.allman@xxxxxxxxx>]

I have my house wired up with Insteon.  In several places I have two
switches next to each other that are also linked to other switches.
If you press both switches at the same time then the signals are not
delivered reliably to the other end =97 only one gets through.  I can
confirm this on my Mac (running Indigo) =97 only one of the devices is
left with the correct status.  If I send an explicit status request
the display changes to the actual state of the device.  My reading of
the spec is that this "cannot happen", but like so many things that
can't happen, it does, repeatedly.

More info: in all cases these are ICON relays; I haven't tried buying
the full-price switch to see if somehow the retransmission is actually
only supported on the high end.  The switches are all firmware rev 28
with the exception of one that is rev 27.

Questions:
(1) Will switching to the high-end switches fix this problem?
(2) Is there some sniffer software I can run on either a Mac or a
FreeBSD machine (I can dig out a Windows laptop and a Linux machine
too) that will show the low-level traffic on the wire so I can verify
that the retransmissions are not being sent?  I'm using a PowerLinc
2413U.
(3) Is there any other magic I can perform to fix this problem?

Thanks,
eric