This study seeks to introduce flexibility in the established procedure of genre analysis for technical manuals. In this study, a number of different approaches to genre analysis have been discussed, mainly those of Bhatia and Lassen, but considering also the pioneering contribution of John Swales. Both approaches can offer important perspectives on the specific applications of genre models. Within this context, the book must be of particular relevance to Inger Lassen's use of genre analysis model for technical manuals and previous studies undertaken by Vijay Bhatia in the area of business and law. However, neither of the two may be statistically applied to all technical or specialized texts, due to the fact that specialized texts are continuously changing and evolving and, therefore, genre models must fit in these communicative changes. Consequently, it is suggested that genre models must be subject to flexibility during the process of text analysis, so that the communicative ideas that govern this type of discourse can be properly adapted. Lassen's prototype has been applied to the sample technical manuals of a natural stone product, Silestone, in order to evaluate the occurrence of moves, steps or sub-steps in different types of technical manuals and to find out relevant variations which might be applied to Lassen's model as a result.