Costco works differently than some other stores. Although I'm not sure if this is the case for LMs, many of the products are essentially sold on commission by the manufacturers at Costco. In other words, Costco doesn't buy and resell the stuff, the manufacturers have Costco sell it and Costco takes a cut off each sale. So Costco doesn't really manage stock in the same way. Every Costco has different stuff, and some things will be there for one day only before it sells out. If you spend enough time going to Costco, you'll find the "good" ones.