Manufacturing Corp. is engaged in the business of making and selling specialized machinery to the automotive industry. In its business, Manufacturing uses large quantities of steel. In July, Manufacturing entered into an agreement with Steel Co. under which Manufacturing agreed to buy rolled steel exclusively from Steel Co. and Steel agreed to provide Manufacturing a 10% discount from the price it charged its other customers. Steel agreed to the discount because it expected to sell large quantities of rolled steel to Manufacturing.

In September Manufacturing started using more plastic in making its product. The result of this change was to cut Manufacturing's needs for Steel in half. Since Manufacturing is now buying less steel, Steel Co. has refused to grant Manufacturing Co. the 10% discount. Manufacturing has refused to pay anything more than 90% of the amounts Steel claims it is owed. Steel has refused to ship steel to Manufacturing unless Manufacturing pays the 10% difference. Manufacturing has therefore been forced to purchase steel from other steel companies.

Source: http://www.uky.edu/Law/exams/Content/1991x.htm

your task is to draft arguments on behalf of Steel Co., including defensesit may have if sued but Manufacturing Corp.