Looking at the website its apparent that they use an automated sytem which calculates shipping based on the total price of the order.

This is a simple way to calculate shipping cost and is not uncommon. One problem is that sometimes it results in excessively high shipping charges when one buys small but expensive items.

My question to you is did you email the company with a polite email asking if they could reduce your shipping charges. You might find them accomodating. I suspect that the overcharge is not a deliberate attempt to gouge you.