*People from South Island have cheaper unit prices due to the lines company they are with. Your unit price price is determined by region, tariff configuration and annual consumption.
*You average daily consumption is under 5 units a day at this stage and others could be more than triple that.
*Your meter is on an uncontrolled plan producing a slightly more expensive unit price where others sounds like they are on a night and day metering set-up producing a cheaper unit price.