I'm guessing Eric will chime in, but here is what I think happens based on this post:
http://www.turbotweak.com/forum/index.php?threads/6-0-target-a-f-question.1620/
(note: 6.0 chip in the post is nearly the same as 6.1 with the exception of you having to use the 'pedal' method to change parameters.)
-The chip will run normally around town with no/low boost. It does not use the wide band for this; it uses the normal O2 sensor.
-With wide band turned off, it will use parameter 4 for WOT fueling across the board. You can still adjust parameter 4 for the fueling.
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