is all the above with running dual WB's?Ideally each bank will only be a few % off from each other, this is completely normal. I have seen some cases where a bank is way off from another, this usually means some kind of mechanical issue but not always.
You can deal with this in three ways...
1. if its a minor discrepancy [usually in cruise and idle] just let ego correction work it out.
2. Like above but you can trim one bank by linking all those cylinders together in the cylinder trim tables.
3. setup dual tables 1-4 ve1 5-8 ve3... this requires going into the dual fuel settings and setting it up, works very well if the simpler methods are not cutting it.