Utility companies - like other investor owned companies - are under increasing pressure to do more with less. The hand-holding of customers that used to exist is no longer available for small, medium sized, and even large customers.
Ongoing efforts to implement deregulation are creating a regulatory climate that is increasingly complicated and dynamic.
Utility tariffs specifically state that outside certain very basic responsibilities on their part, the onus is on the customer to ensure that they are not paying more than necessary for the services they receive.
While utility companies are not out to intentionally overcharge customers, they also do not devote as many resources to making sure their billing is accurate as they could. Many customers find that - either through errors or not being savvy customers - they are paying their utility companies more than those companies are entitled to.