We are on a fixed tariff for another 18 months ( lucky us ) and a friend suggested a possible way to unofficially extend this tariff , what has been suggested to me is , as we read and submit our own meter readings we should add a bit extra usage every time we record our meter readings so we effectively pay more in the short term and build up a reserve of energy we have paid for but not used and as we come off our fixed term we do the opposite.
Seems a good idea to me , but where is the flaw in this ?