Sears Developer Network

I am trying to use the local search, via keyword to search for products available locally/in store. I tried searching for Playstation 3 for zip code 01702. This returns a positive result via XML (StockIndicator = 1), however when I browse through the Sears website, the item is not available in many of the local stores? Which API do I use to check for local inventory? pointers would be welcome/much appreciated