Profit's are not as repetitious as they would seem at first glance. A barrel of crude has 42 US gallons, after they're all through refining the hell out of this you'll get about 19 gallons of raw gas. This will give you a pretty good breakdown of here's where you start, here what you end up with:
WHAT A BARREL OF CRUDE OIL MAKES
And depending upon where the crude came from you may well get less. Interesting thing is "The sum of the parts can exceed the whole." But you're pricing your end product(s) and you know the price of your next 5 million barrels is going to cost you 5% more. Do you wait for delivery, or do you factor that into 'today's prices' for the expected cost of deliveries.
World price of oil goes up another 2%, do you wait until the Tanker is tied to the dock to take that into consideration?
I think "now" if you've got your head screwed on tight. But in the interim the Tanker hasn't hit the dock yet, but you're collecting what you KNOW you're going to have to write the check. So, TEMPORARILY, Exxon's bank balance goes up .... temporarily.
Now lets look at the above from another angle. You have/control major producing oil fields vs. having to buy the bulk of what you get off the World Market. Now if you price what you're paying 'pennies' to get out of the ground at world market prices ..
KACHING! KACHING!! Now we're talking real money Boys and Girls.
But that still begs the question

of given how much oil exists in the US why aren't we drilling for same? Clue:

It's not because the oil companies don't want to.