We have a staging website and here is the link in question - [url removed, login to view]
We have implemented a multi add function where you can input quantity for each related product then upon clicking on "ADD ITEMS TO CART" all the products with quantity fields filled in will be added to cart.
The problem is after clicking on the big black "ADD ITEMS TO CART" button, the side shopping cart block and the shopping cart link in the top right corner - they only show 1 item's price. The strange thing is once you go to the shopping cart URL then all the product display correctly.
The extension we are using only has 2 files - a controller and a helper file.
This should be a quick fix if you know what you are doing.