IELTS Band Score

According to this website (http://ielts.calculator.free.fr/), here are some tables made by myself, for both academic and general training reading sections and also for the listening module witch represent the balance between the percents of understanding (correct answered questions) and the grade you get represented also in percents from the highest band. A very important thing to notice is that is not important witch questions you answer well, the simple ones or the hard ones, the only criterion being the number of correct answers. Let's see how fair is it!...

We can easily notice that, on the inferior bands from 1 to 5, they are pretty generous, probably because you will not be able to do anything you need with a 5 band score, between 5.5 to 6.5, the situation is getting fair on both reading academic and listening, but they really kick your ass at general reading. Please take a look at 26 correct answers in the reading general chart, at 65% level of understanding you get only 56% from the maximum grade, witch means a 9% difference. On a normal scale from 1 to 10, this means they cut you off 1 point from the deserved grade. ...Finally the worst situation is at 29 correct answers, where the level of understanding is 73% and the band you get is only 61%, that means they cut off 12% from your grade. Isn't this a different way of stealing? Stealing is a crime, dear lightning heads from Cambridge!