In this paper, we analyse in detail the selection of financial products. We apply the index of maximum and minimum level for the selection of financial products and we analyse what we have called the unification point between the Hamming distance and the adequacy coefficient. First, we study this situation for the case of maximum levels in the characteristics of the ideal financial product. Then, we generalize it for all the possible situations where it can be found. Finally, we study the unification point in the index of maximum and minimum level. The result found shows a transformation of this index into the Hamming distance.