If you are truly OCD, I hope you used the specific gravity of the oil and checked the weight of the oil to calculate the volume. You should also use a calibrated measuring vessel.
On a related note, my slightly OCD family was splitting a bottle of wine that my sister brought to my house from France. For 6 glasses, we figured that we could just use one of my glass measuring cups and put 125 ml(FYI 750/6 = 125 to save you the math) into each glass. After filling all 6, we still had over 200 ml in the bottle.
It turns out that the measuring cup is wrong. This also explained why the tile grout I mixed didn't seem to have enough water in it - the first and last time that I measured by volume instead of using a scale. Obviously, measuring water with a scale is a pretty straight forward task. Oil would be a nightmare with all the different specific gravities and batch variations.