Wrong quantitiy when adding product

I try to add 2 pcs of packages to 1 selling product:
http://prntscr.com/10o8ncb

But when I add that product to cart I see only 1 pcs of packages was added:
http://prntscr.com/10o8oom

But, when in the cart I click “+” button to increase the number of products the forced sell makes 4 pcs of packages which is correct, after that if I click “-” to make the amount again to 1 pcs it makes back to 2 pcs which is also correct

The page I need help with: [log in to see the link]