Owing to the spoilage inherent in all manufacturing, printing and production processes it's not possible to supply an exact quantity.
For instance one side of a sheet is printed, when dry the other side is printed, then it's trimmed, folded, collated, saddle-stitched and so on . . . until it's finally ready for delivery.
In the course of each production process a certain number of sheets can be wasted (spoilage).
We always print many more copies than are initially ordered to allow for this wastage. On a good day we won't waste any and you'll receive slightly more (overs) - on a bad day you may receive slightly less (unders).
A normal working tolerance of plus/minus 10% on smaller quantities is normal throughout the printing industry. On larger quantities this comes down to plus/minus 2% or less.
Please bear this in mind when placing your order.