What does the "Count weight from" setting mean?

What does the "Count weight from" setting mean?

Starting from version 1.9.0, it is possible to define when to charge extra for the excess weight of the products in the cart. It can be done with the Count weight from option available in the rate settings (when you're editing or creating a shipping rate inside a particular shipping method):



Once product weight in the cart exceeds the Count weight from value, the Fixed Rate per 1 unit of weight option will be triggered. According to the above example, $1 will be charged per each 1kg once the order weight is more than 10kg. 

The frontend result is provided below, here the shipping cost has been calculated according to the formula: (15 - 10)*1=5. Excess weight of 5kg was charged with $1 per each extra kg, so the final shipping rate is $5: