One question about the inflation:Is it possible to add my own value at the inflation(e.g.:3%) without take into account the interest rate?For example at the Economics tab there is an option to add the Annual interest rate ,but this takes account of the interest rate given by the equation: i=(i'-f)*(1+f)^-1

You can assume any nominal interest rate and any inflation rate that you want, but all you can enter is the real interest rate, which you can calculate with the equation that you quoted below.  If you are asking whether you can apply different rates of inflation to different components or different fuels, the answer is unfortunately no.