In safety- and security critical contexts such as crises management, emergency response and defence, actors must be able to manage complex problems. In this paper we study the organisation of functional competence within teams engaged in dynamic decision-making tasks, such as teams working within a command and control process. More specifically we investigate if team performance is affected by the level of variety of functional competence within teams, in relation to the level of complexity of their task. 18 teams with four members each, participated in experiments with a simulated microworld. Our results show no significant difference in the overall performance between the high variety teams and the low variety teams. However, process measures, such as decision-making speed, and the capability to extinguish fires in the simulated world, still indicate a performance advantage for the low variety teams, at least at a relatively higher level of external complexity.