Diagnosis
A negative serial switching consumption value was determined atinstallation &v1& in the period from &v2& to &v3&.

System Response
The system cancels billing.

Procedure
Check and correct the meter reading results for the installationsconcerned.
Please note that all consumption values for secondary installationswhere installation &v1& is defined as the
higher-level installation are deducted from the consumption value forinstallation &v1&.