Best answer by woz
The statement is produced once a month, the billing for units used is up to the statement date, so unless you give a reading a day before the statement date there will be some days from when you submit your reading, to the date of the statement, where PP have to guess what you use.
Any readings you give WILL appear on the statement, it's only those days after the given reading which are estimated, and usually the closer to the statement date you give the readings the closer the estimate will be. It's usually pretty close anyway.
Does that make sense?
Why, would you estimate my gas and electric consumption, when I have given you the actual reading. A confused senior. Chipper.