Lean Construction (LC) and Building Information Modelling are the two methodologies linked by the same objectives. The former is an industrial optimization, which want to achieve the aim of performance increasing with the application to the AEC industry. These two concepts leaded Melzo school tender process writing. There are huge differences from a traditional process approach compared with BIM one, which leads project to a coherence high level. A deep LC principles understanding entail a distribution of the point to the different categories. The importance of LC criteria, in terms of points, imposes to the companies a change in the mind-set, from a lowest bid approach to a performance one. The study is based on the analysis of the responses to the case study procurement. Different competitors answer differently in function of Lean principles weight and their knowledge. The change in the state of mind leads the companies to offers value. In some cases, even if, many points were not able to change their behaviour. The behaviour modification will be a difficult transformation for the AEC sector.