improving option valuation precision erms stinson zhiyong wei group need make change please follow zhiyong jeremy wong allan stinson gibner 08 23 2000 09 54 allan severude hou ect ect cc vince j kaminski hou ect ect paulo issler hou ect ect eric moon hou ect ect ed mcmichael hou ect ect zimin lu hou ect ect subject improving option valuation precision erms allan paulo issler group working eric moon structuring recently tracked reason slight mis match option pricing erms vs structuring spreadsheets due fact option valuation functions erms use slightly less accurate approximation cumulative normal distribution would happy work right person update erms code order close discrepancy please let know would like proceed correct person address mainenance erms please let know contact thank stinson gibner x 34748