I just got off the phone with Banks and they felt that the most likely cause is the cable extension (supplied by banks as part of the Powerpack kit) that goes between the factory wireing and the sensor, or the sensor it self which is located just before the Y pipe. Banks also belives that Bank 1 refers to the passenger side.
I'm in Yuma and will go check this out after the exhaust has a chance to cool and the outside temp drops to something less then 100. May not be untill the end of september or maybe tomorrow morning before sunrise.