Is someone stealing my electric?

CashStrapped

You say that on the 5/10 they said your reading was 43.19. That is not a meter reading, that is your calculated usage over a certain period. What you don't say is how they calculated that and over what period (number of days)

The best thing to do is go through your bill history and write down all the meter readings as they were given. Make sure you look which ones are actual meter readings (usually with an A or C next to them) and which ones were estimates.

Then ignore any estimated ones and work out the usage between the actual readings.

For example.
01/01/16 reading xxxxx (actual)
13/02/16 reading xxxxx (actual)
10/03/16 reading xxxxx(estimated) ignore
05/05/16 reading xxxxx (actual)

It may be that estimated readings are skewing some of your calculations.

So looking at the actual readings work out the usage and divide the result by the number of days between the two readings.

That will give you an accurate daily average use over that period.

Along with my meter test method above you could also buy a meter monitor. This gives you a visual display so you can monitor your use live.

Good luck!