I don't know how typical this is of Costco in the US but where I am in Canada, I can't figure out what on earth the oil buyers for Costco are doing. For the most part I find Costco does an excellent job of picking products for their good quality but limited selection approach. I spend more money than I care to admit at Costco in a year but never buy oil. Why? They keep the wrong grades at least for this region of Canada. Current stock is 10w30 Formula Shell, 10w30 Castrol GTX, and 5w50 Castol Syntec. I can't remember the last time I put a 10w30 oil in my vehicles, and I know I never have, nor ever will use a 5w50. The price is good for Canada on the Syntec at $5.66 a liter, the same as the Walmart TECH2000, but 5w50?? Any thoughts as to what's up with Costco, at least in Canada? Walmart obviously is a US company as well, but at least they seem to have the required grades figured out. Don't think they even stock 5w50. If it were my choice I would keep the low cost 10w30 Formula Shell to hit the bottom end market for the old school crowd, and switch the GTX to 5w30, and the Syntec to 5w30 or even 0w30 at least for the winter months.