Yes.  If a meter is not properly sized, it might be accurate for the range of flows it is designed

Although there are many ways to provide a better level of confidence, there is only one true way to calibrate

An audit is required for many reasons. When there is a balance error where the contribution of error could be

A general answer is NO.  This would depend on the benefit or predicted return on the investment to conduct such

No, it is not required if you are willing to accept the numbers as is.  Meter calibration is part of

The main categories are Supply Input Volume, Authorized Consumption, Water Losses, Revenue Water and Non-revenue Water. The sub-categories are Billed