Losses due to meter inaccuracies are n nothing but a difference between actual energy supplied to the consumer through the meters and amount registered by meters.
When meters it gives negligible errors in the metering, it gives negligible errors in the amount registered by meters.
When meters are new and it’s started being used for metering, it gives a negligible error in the measurements in an earlier phase of its use. As it becomes old it starts introducing errors.
As it gets older its mechanism slows down and it under records the usage of energy.
This issue was with mechanical meters which are being out of date now.
Latest meters in the system are electronic and these meters don’t this problem with its age.