Thanks, Scott.  Lots to think about.  What happened on my overcharging episode was that the sensing wire was loose at the alternator.  Result was that the voltage read by the regulators was some 3V lower (!!!) than the voltage I measured at the battery.  Hence the regulator put the alternator in bulk when float was indicated!   The only way I could see that was by connecting my laptop to the alternator via the Mastervolt Masterbus.  Once I tightened the connection, the sensing wire read .3V HIGHER than voltage at the batteries which makes sense because of the resistance in the wiring.    Stuff happens!