Staley Co. manufactures computer monitors. The following is a summary of its basic cost and revenue data: Per Unit Percent Sales price $480 1% Variable costs 312 _ Unit contribution margin $163 2 [ Assume that Staley Co. is currently selling 600 computer monitors per month and monthly xed costs are $80,000. What is Staley Co.'s margin of safety (MOS), in units, if 600 units are sold and all costs and revenues are as budgeted? (Round intermediate calculation up to nearest whole number of units.)