Blue Line Powercost Monitor

If you are concerned about the accuracy of the data from your meter than the Blue Line is not the best fit for your needs, as it reads the same errors.  Consider getting a device that connects at the circuit box, such as the eMonitor or Eyedro.  However, be sure you understand how your electrical system is wired, if you have multiple panels that are wired directly to the meter you would need multiple monitors to capture total use. Also, if you are switching your home "off" while out of town do so at the circuit box or equip your house with smart power strips, as even when everything in your house is turned off many electronics still have a standby (aka vampire power) draw. Its also worth making sure you have traced your electrical wiring and are certain there are no additional circuit boxes feeding off the meter - For instance a friend purchased half a duplexed townhouse and was amazed at how large his power bill was, as it turns out it was because he and his neighbor were fed by the same meter but he was the one who got the bill.

Power companies have not publicly accepted any data source other than their meter as valid, however if you have installed a monitor and it is showing a wide variance between your power use and what the power company says your meter is showing and your power company is unwilling to double check the meter for accuracy or help address your concerns, OR if you are convinced that your utility is committing fraud, then you should contact your state's Public Utilities Commission's consumer/'ratepayer complaints department and discuss with them what sort of documentation they would need to see to launch a review. 

Before you do that though be sure you are comparing the same period, for instance my electric bill runs from the 14th of one month to the 13th of the next, so to get the right comparison data I'd have export daily usage from our monitor's webportal and slice and dice it a bit.