Why? Can you explain why these additional few percents of German oil production was critically important in 1940?
Germans had no problem replacing this source in 1941.
As previously stated the German reserve was not much more than a million barrels in 41.
42 they grounded the Navy was struggling and the push towards the Caucasus was an attempt to grab more fuel.
Army group center and north didn't advance much.
So they put everything into one push the oil situation dictated where they had to go and how they could do it.
It also dictated them using the BF109 for the entire war as it used a different grade of fuel.
It also explains why they kept trying to make better tanks over building more they couldn't fuel anyway.
It even effected their engines. Several aces died due to engine failure from crap fuel.
British had the best engines, they also had good fuel.
How do you make an American fighter better? Put a British engine in it.
How do you make a Soviet fighter better? Put a British engine in it (Mig 15).
The Germans did do a lot of the thing the Allies did the difference was copious amounts of fuel.
More women worked in agriculture in Germany less mechanised so they weren't available to work in factories like Allied and Soviet women.
And even if they were they couldn't fuel anything extra they built.