We consider that these should be reviewed every four years to ensure these keep sufficiently current with the actual costs of running a vehicle. Moving to a four-year recalculation period also seeks to compensate for the removal of the ability to reduce the number of "available days" again lowering compliance costs as noted below. The one modification that Inland Revenue makes to these running cost calculations is to substitute the cost of petrol with fuel watch data from the Ministry of Business, Innovation and Employment (MBIE) because this is more up to date than that used by the AA. We propose continuing to mirror the calculation of the mileage rates to determine the FBT value of a motor vehicleshorten