Hi ModernMan,
Rest assured, I've already asked our energy team to look into this and naturally, I'll let you know their repsonse as soon as I have it.
I'm not an expert, but I think - and will confirm or correct this later - that the differences are to do with the calculations made around seasonality and estimated energy usage. I'll let you know in reply to this post as soon as I have more details.
If you'd like to speak to our team, they'll be more than happy to take you through it: 0845 345 1296.
Thanks,
Graeme
Community Manager
graeme.delap@moneysupermarket.com