Well, they have to do something to sell 10W40 oil ! When cars started requiring 5w20 and 0W20 synthetics, my local Walmart was out of them all the time because there shelves were clogged wit rows and rows of 10W40 that almost no one was buying. Car manufacturers had been recommending against 10W40 for years but there is always someone that thinks that if 10W30 is good, 10W40 must be better. I think that that somebody was (mis)managing our Walmart. They eventually cleared out the stock, I think they must have moved him to the customer (non) service dept.
Oil leaks wll be easy to find using the Sniff Test