Service choreography allows the composition of services in a collaborative way, taking advantage of various benefits of P2P systems. The existing modeling approaches to evaluate choreographies are the interconnection and interaction models. However, these approaches don't evaluate choreographies focusing on QoS or in the earlier stages of development of the distributed application. This paper proposes an approach to assess the impact of QoS attributes specified in a choreography interaction model. With our proposal it is possible to establish requirements for QoS and SLA in early stages of development in order to plan the capacity of the network elements connecting the hosts involved in the enactment and deployment of the choreography.