Purpose - The purpose of this paper is to provide a solution for differentiating must-be and attractive quality dimensions of the Kano model. Design/methodology/approach - The distance between the three curves of must-be/attractive dimensions has been assumed as equal and the linear logarithmic transformation has been used in order to compute new k (Kano category) values for differentiating the dimensions. Then, the new values have been examined in a case study at the Amin Parvaz air travel agency in Isfahan and the results have been compared with those of the traditional Kano approach. Findings - The new methodology as an example suggests k-values of 2, 3 and 4.5 for less, moderate and more must-be dimensions, respectively; and 0.5, 0.7 and 0.98 for less, moderate and more attractive dimensions, respectively. Also, the results of the case study indicate that the new methodology is significantly effective in differentiating Kano dimensions and provides more accurate prioritization of the dimensions compared to the traditional approach. Research limitations/implications - Although the new methodology evolutes the Kano methodology and could benefit other quality tools and techniques such as quality function deployment more effectively, the case study is limited only to a particular service company and the questionnaire is long and time-consuming. Originality/value - The proposed solution provides new enhancement into the knowledge of quality management. It is believed that the proposed approach facilitates analysis and decision making, particularly in cases where the frequency of attractive, one-dimensional and must-be dimensions are equal.