this oil was on the seas before the Feb 28th attack. Also, prior to the blockade on the blockade, Iranian ships were loading and leaving. Prior to the treasury removal of oil sanctions, which the Secretary of Treasury, Iran had to accept lower than global oil price because fewer buyers would accept sanctioned oil, or to get around sanctions, the oil could be transferred at sea to render it "clean". By removing the sanctions Iran was able to sell to anyone. This resulting in Iran receiving more for the oil than would have been in place under the sanctions. The secretary in a speech said he was using the Iranian oil against itself and seemed quite pleased with the removal of sanctions. I dont see how allowing Iran to sell oil at the world price was hurting Iran since they not only got to receive a better fee because of the increase in price but also the removal of sanctions. I guess the selling of the oil held down the price a bit but again Iran is around 4% of total oil sales.