1. A computer-implemented method of managing workflow for a print shop, comprising: maintaining, in a computer-readable medium, a data set comprising prospective print shop order data for a plurality of customers over a plurality of unit time periods, wherein each of the unit time periods has a corresponding demand level based on the prospective print shop order data for the unit time period; determining, by a processing device, a demand variation level that corresponds to a measurement of variation of the demand levels for each of the unit time periods; selecting, by the processing device, a first customer for rescheduling of print shop orders, wherein the first customer's print shop orders have an original processing period that corresponds to one of the unit time periods in the set; modifying, by the processing device, at least one of the first customer's print shop orders to yield a modified order that has a revised processing period, wherein modifying comprises: determining, by the processing device, a matrix from the data set, wherein each row in the matrix corresponds to a customer and each data point in each row of the matrix corresponds to a unit of measure for that row's customer's print shop orders per unit time period, determining a set of values for the first customer, wherein each value in the set of values corresponds to a measurement of the first customer's print shop orders in each of the unit time periods, and generating a volume scaling modifier for each value in the set of values, wherein a sum of each of the values multiplied by its corresponding coefficient equals a sum of each of the values, wherein generating comprises selecting a coefficient that minimizes the function: J = 1 m - 1 ⁢ ∑ i = 1 m ⁢ ⁢ ( C i · y 1 ⁢ i + y 2 ⁢ i + … ⁢ ⁢ y ki - A _ ) 2 , where Ā is the average daily volume and is independent of the values chosen for each coefficient; wherein the revised processing period differs from the original processing period and corresponds to a different one of the unit time periods of the set, so that movement of the modified order from the original processing period to the revised processing period reduces the demand variation level.