nbcman
Donor
There is also the not minor reality that the U.S. would be ill-disposed to sell those extra six million barrels to the UK if London has just given DC a giant flaming FU by breaking the embargo.
The only period where the UK might consider to sell oil is after the Fall of France (pre-Embargo) which was also the time where the UK voluntarily closed the Burma Road from July - Sep 1940 because of Japanese pressure. There is no chance that the UK or the Dutch by proxy would circumvent the US oil embargo of July 1941.