Assumptions of the Kano Model
Note that the model by Kano is aimed at finding the average appreciation of certain quality factors in a representative group at a moment in time when the questionnaires are collected.
There could be valuable customers with a different profile as well. This may require a seperate marketing effort.
You'd better make sure the interrogated group is representative...
The classification of and the happiness about certain attributes may change dramatically, even in a short time period.