Oil is sold by the truckload. It simply would not be efficient to send a truck out for less than a full load. Oil is produced into storage tanks and the actual production is reported to the State. Oil is sold whenever a truckload has accumulated. The difference between production and sales in any given month will be reflected in the change in tank inventories from the beginning to the end of the month. In some months sales will be greater than production, some months it will be less. It will almost never be the same. When they report to the State every month the numbers must balance out or the State won’t accept it. That data is available at the State website if you want to go to the trouble to look it up, but I seriously doubt you will find any discrepancies, because like I said, the State won’t accept their report if it doesn’t tie out.
As far as the price is concerned, I’m not sure what you mean by “…$8/bbl less than the lowest shown price for the month.” Lowest price shown where? If you are talking about NYMEX oil like what you see quoted on TV every day, that would not take into account any basis differential and or any gravity adjustments, both of which will factor into the price received at any particular place in the country.