The back of your bill contains a section called Usage Details. Here you will find the meter reads used to calculate your bill.
(A) after the reading indicates an actual meter reading
(E) after the reading indicates an estimated reading
(C) after the reading indicates a reading supplied by you

You'll notice the Usage Details can include up to three reads:
Previous Reading: Your bill is calculated from this reading.
Interim Reading: any actual meter reads received during your billing period will be included here.
Present Reading: your bill is calculated up to this meter reading.