How is invoiced the natural gas consumption if the measurement device inaccuracy does not fall within the permissible limits?

If the metrological check has found that the measurement device inaccuracy does not fall within the permissible limits, the contracting parties are entitled to initiate the recalculation of the natural gas volume supplied during the last 3 months, taking into account the arithmetic average inaccuracy established in the metrological check. Recalculation can be made only when the metrological check has been performed within the period set between two consecutive metrological checks.