In some industries, simulation and modeling techniques are a widely accepted, integral part of system design, while in others these techniques may be perceived as expensive, unreliable, or inconclusive. Within the Manning Affordability Initiative (MAI), which was funded by the Office of Naval Research and managed by the DD-21 Program Office, we have attempted to demonstrate that simulation and modeling techniques can play a significant role during the design of future combatants, especially in light of future Naval goals to optimize shipboard manning. The MAI used a warfighter-centered design approach to developing a prototype air defense warfare (ADW) system, and human-in-the-loop data was collected from the watchstations in use today and from the prototype watchstations. Under a simulation experiment, the Integrated Performance Modeling Environment (IPME), a discrete event simulator, was utilized to represent a demanding ADW scenario, and models were created to simulate performance for ADW teams using today's watchstation and then to predict the impact on performance that can be expected from the prototype. These complex models include multiple operators, dynamic operator task assignment configurations, workload tracking, internal and external communication network activity, and processes such as air track detection, track identification and re-identification, monitoring of changes in track profile, threat evaluation and engagement. This paper discusses the process of calibrating, verifying and validating models of the current and prototype watchstations, and present the conclusions made.