Meter reliability 

Electric meters are extremely reliable and accurate devices. They have to be. There are hundreds of millions in use through out the world recording billions of dollars of electric sales each year. The quality control on these sensitive devices is extremely high.

Never-the-less, meters occasionally malfunction. Very few of the meters checked for suspected accuracy problems are found to be inaccurate. Of those, nearly all are found to read low. That is, they record less usage than actually occurred.

When meters are found to read low, APS adjusts them to read properly. When the occasional meter is found to read high, APS adjusts them to read properly and issues a credit for the estimated overcharge.

There is a $50 service charge when a customer requests a meter be checked for accuracy and it is found to be within specifications, which is most of the time.