I've been doing some light reading on quality control in manufacturing. Lots of applicable stuff in there.
"The consultant was going about it the wrong way. Using the manufacturer's claim as the lower control limit (action limit) is confusing special causes with common causes, making matters worse, guaranteeing trouble forever. A wiser procedure would be to get statistical control of the machine, under the circumstances in place. Its performance might turn out to be 90 per cent of the maximum speed as specified by the manufacturer, or 100 per cent, or 110 per cent. The next step would be continual improvement of the machine and use thereof."
– W. Edwards Deming