Agreed. In fact there are a couple of posts around here somewhere where all of that is explained. Mixing E-85 with race fuel is a no go as well. Any of the pretoleum based octane boosters ( including lead ) will not effect E-85. In fact when E-85 is mixed with these fuels it dilutes the mixture and can actually lower the octane rating of your race fuels. E-85 has great knock supression qualities itself. If your going to really run high boost, get some bigger injectors, run 100% E-85 and be done with it. I actually have 2 chips so I can switch if I want from 93 back to E-85 and so forth.
Remember E-85 or mixes thereof cannot be rated by the RON or MON methods.