If we had to get 40 or 50 stock positions from your office every time we rendered a single page the website would run very slowly. So we use a cascade of memory and database caches to keep the stock position. By default the cache value expires every 4 hours and the value is also updated when a sale is made through the website.
The cache time-out is configurable. We also provide cache control features so you can void the cache for a single stock code or all product if you need to.