I doesn't need a meter change before checking a utility bill. Since going on a combined bill, we have had a number of errors which we have had to question, usually to the suppliers advantage initially I might add.
I think one of the best recently, was when a television consumer program was highlighting some of the errors being made. One person was even threatened with a court summons for not paying their gas bills. The only problem was the house was all electric only, and had always been.