Why does this matters in your case?
It matters (sort of) for a few reasons:
I would prefer to have an high enough E on the first fill-up to get full HP. (Yeah, just personal preference.)
I also believe the PCU will do some learning on the first tank of Exx. I have no hard evidence, but I would expect the PCU will watch, adjust and remember. (Maybe I'm expecting too much.)
If I could get a very high E (like E85 for real) I can cut it with Sunoco 100 I get at the pump locally, I figure that would a very convenient way to make a nice and safe race fuel. (And relatively CHEAP, the way I like it!

)
I don't like to dance close to limits, if I need 65%, I aim for 70. (Yeah, I know...)
Thanks for the link to the calculator, just this morning I made a xel spreadsheet to do just that!
