Is anyone else having trouble find these in the 5qt. jug? None of my local auto stores, big chain stores and even online stores like Amazon, Walmart, etc. seem to carry them. they are listed, but at check-out it says "out of stock". I can only find them in the qts. at $5.79 and never enough at one store to get all 5qts. I did called Pennzoil customer support and verified its still in production. I’m at a loss …