first off i would say that your results are in the normal range.
it will take a little for it to come back around to normal after having run it as it needs to "flush" it all back out.
on average if your not saving over 20% then it is just not worth the hassle unless your using it for performance, and most stock vehicles just dont NEED it, or can make best use of it.
here is the skinny on it. on the average driven vehicle it is usually just not worth it. dont mean it is better/worse just not mathematically worth it. the benefit is high performance stuff that takes premium or above, and the results are almost magical in a boosted vehicle ( that has been tuned correctly) as most vehicles that are boosted require premium or greater, and e85 is like running a mix of race gas and alcohol (because it is a form of it) the cooling properties of alcohol are awesome and to a point you can add more boost by simply adding more fuel. which means more power. and when prem is 1/3 more than reg and race fuel 5-7$ a gallon running e85 is dirt cheap and street legal. it just requires more of it, 20% in a stock type setup and up to about 40-50% more in a very high performance setup.
