Fuel is usually mixed by the same refinery nearbye all the same stations. Go to a different area, different refinery, different %. In Utah E70 was really more like E66. All the same company for the whole state. All year round because E70 was mandated all year for silly high altitude reasons.
Stay in the same area and you will probably never see much difference in tune. Get fuel from the same place and you will probably be fine. Some places like Costco or others that buy bulk from different places might see more differences because the supplier is not consistent. Unless you have proven you have E10 and Ezero in your tank and seen the same tune (which would make no sense) then you can't say it.
I don't even bother with the AFR table. I built one originally but then I decided that its easier to fix up my own VE table then deal with the stupid wandering AFR in closed loop.
I agree with Ed that changing required fuel makes more sense. The only important difference between E85 and 100% gasoline is the stoic. Change the stoich in required fuel to match your Ethanol % and your tune is spot on. Just because VE tables are more easily switched doesn't mean it makes sense.
If it was me, an Ethanol sensor would directly change required fuel stoic instead of trimming VE. It might work but it does not make logical sense to change VE based on your fueing. It makes talking about engine performance or how engines actually function, very confusing. The only sensible thing about the VE trimming is that it does make sense to have a spark trim and its probably easy (lazy) to use that programming loop on VE. That or maybe required fuel can't be modified on the fly.
I like to think of VE as what it actually is, something that does not change. It is a characteristic of the engine.
SBECII 3.0 on true E66 will run 18:1+ when the normal Gasoline runs out from the fuel lines. That is open loop cold start. I have a video of my first cold E85 start (with E10 still in the lines) but I guess I never uploaded it. That is something that happened between the first junkyard motor startup and running at the track on that motor. Closed loop it should easily be able to drop that back down to 14.7 and destroy fuel economy. No way to trick the ecu unless you lie about AFR values with your wideband (which you can do with E10 and get much better mileage).