The gemara calls one who reviews their learning 101 times an "oved elokim", but one who only reviews 100 times is called a "lo avado". This may be obvious, but worthwhile to speak out. Based on the mashal that the gemara gives, the point is not just to encourage reviewing an extra time. The parable of the donkey is that a standard donkey for rent can travel 10 parsa and cost a zuz. If one wants a donkey to travel 11 parsa, although it is only 1 extra parsa a "standard" donkey can't make it, they need a "premium" type donkey, and therefore the cost will be 2 zuz. They are not just paying for the extra parsa they are paying for riding the entire 11 parsos on a premium donkey. The point of the gemara is to say that one who reviews the extra time, in contrast to one who reviewed one time less, is not just missing one review. Rather they are a totally different type of "donkey". The numbers of 100 and 101 are only examples that fit into the gematria, but the point applies to any number of times that one reviews. The clarity obtained from the extra time that one goes over the material makes him an entirely different type of person than one who reviewd one time less.