Sail On manufactures flotation vests in Charleston, South Carolina. Sail On's contribution margin income statement for the month ended January 31 , 2018 , contains the following data: (Click the icon to view the cost information.) Read the Requirement 1. Identify each cost in the income statement as either relevant or irrelevant to Sail On's decision. Requirement 2. Prepare a differential analysis to determine whether Sail On should accept this special sales order. (Enter decreases to revenue or increases to costs with a parentheses or Data table Suppose Overlook wishes to buy 4,800 vests from Sail On. Sail On will not incur any variable selling and administrative expenses on the special order. The Sail On plant has enough unused capacity to manufacture the additional vests. Overlook has offered $6 per vest, which is below the normal sales price of $17