They must be, mine are different again, I've worked out it's about £50 a month difference off the projected costs but we didn't live in the house last winter as we had work being done and the winter before we had the heating on all the time as we had no insulation in the roof due to doing a loft conversion so it's really hard to gauge, I also now only use the gas boiler for showers and the kids baths rather than heating, they are hounding me to have a smart meter installed for gas but I keep fobbing them off as they wouldn't help me get the meters relocated last year when I needed them on another wall, sod em!