This paper seeks to examine how a case company exploits new staffing procedures and enterprise system (ES) functionalities in order to improve allocation and control of project resources. The paper relies on qualitative data collected through an in-depth case study in a large European high-tech company over a period of one and a half years. In order to understand the system usage in the case company the paper employs institutional theory and Orton and Weick’s concept of coupling. By combining the concept of coupling with the elements of system usage - work assignment, user, and system –, the paper explains why system usage differs between organizational units. Findings show how the use of new ES functionalities is influenced by features of organizational unit, features of work assignment, individual characteristics as well as target customer. The paper also recommends selective system use in a knowledge-intensive project organization.