This paper presents a performance evaluation in the context of the Aggregation Service (AgS). The AgS is a P2P overlay-tier whose purpose is to aggregate the services and service components maintained by service providers in a P2P Service Overlay Network (SON). The performance evaluation takes into account two metrics: (1) the average path length, and (2) the response time. Both of them are used in the comparison of two environments: (1) AgS and (2) a P2P SON without AgS. Additionally, the searching performance in the environment with AgS is compared with a P2P SON that uses Gnutella as the searching mechanism. The simulation results clearly show an improvement in the performance of the search operations when the AgS is used to the detriment of the searches performed without it. The results also show AgS is better suited for use in small overlays.