I wouldn't even take the chance, I got burned on some Castrol motorcycle oil awhile back from a 3rd party seller which advertised it as one thing but only shipped 1 case which was only 6 qts. Amazon did step in and I did get the money back but I was out of the return shipping. I made the mistake of going through the seller for the return first but sounded like if I had just worked with Amazon they would've let me keep the oil and not return it. I reported them to Amazon but they did nothing about it, I went back and found other feedback where others were also ripped off.
I can't remember how much they screwed me out of but I could've walked into Walmart and bought the same oil for 2x-3x less. If you're going to pay the $20 I would only expect 1 jug.