This paper reports on an application of alternate routings on manufacturing system’s performance, defined as risk of completing production plans. In previous work an integrative methodology was developed in which process planning system IMPlanner was integrated with an FMS simulation module. IMPlanner’s rule-based process selection system performed knowledge intensive task of generating alternative processing options for each feature for parts in production plan. In this paper an updated simulation model using Simio was developed and Simio’s scheduling capability was utilized in order to determine the reduction of risk of job tardiness in the production plans when alternate routings are considered. Methodology is explained and new simulation model described. The experiments were performed on several case studies from machining domain, with a number of alternate routings as input parameters, and different due dates as performance criteria. Results from the updated simulation model were compared with the previous study in which only resource utilization were analyzed. The level of risk reduction with alternate routings is quantified.