The shipping costs are calculated based on your order and weight. The shipping costs for a given shipping address may vary depending on the size and weight of the order. How higher the weight, the shipping cost increases. This is the standard procedure within all the shipping companies.
The provided shipping cost are based on a door to door delivery, but doesn't include any duty cost. The duty cost depends on the local country rule, for example shipping within the EU is free from duty and shipping to the US is free up to a value of 200,00 USD. For more information, please check with your country customs department.