Hi bertux77
The figures you see at the bottom of the Stock Central table aren't a global value, it's just the sum of all the stocks from the items shown on that page. When you navigate to page 2, will sum up the listed products, and so on.
On the other side, the values shown in ATUM's Dashboard are global. So the sum of all the products on your site.
I hope this helps.
Best Regards,
Salva.