1. A modeling and manufacturing execution system comprising: said manufacturing execution system for automatically controlling routing of product lots and production inputs in said manufacturing production line based on a production scheduling model, wherein feedback data from said production line is provided to said manufacturing execution system, said feedback data comprising operating parameters for equipment in said production line and identification of said equipment by type; a database for storing said model, said feedback data and formulae for calculating a production capacity for each piece of said equipment based on said identified type of that piece of equipment and said operating parameters of that piece of equipment; and a simulating system for simulating operation of said production line according to said model, said simulating system using said formulae from said database to calculate said production capacities for said equipment in said production line; wherein each formula in said database is associated with a flag having at least two values; a first of said values indicating that an associated formula is based on actual operation of equipment production of said production line; a second of said values indicating that an associated formula is new and unproven.