Hello, I love the look and the feel of the mauviel m'heritage 250C copper pans but have some questions before purchasing. With a description of: "90% copper and 10% 18/10 stainless steel preserves the taste and nutritional qualities of foods and easy to clean."(from mauviel's website) I'm assuming this means a Stainless Steel surface inside of the pan and NOT tin. However, on some other websites i see commenters stating this is actually tin. Has anyone purchased these and can confirm that I would be purchasing copper with SS and not tin ? I do not want to have to re-tin my cookware. Thanks!