Sorry. I wrote a reply earlier and it got lost in the ether. HIS 308 is a carcass and tread conformation style in the Schwalbe catalogue. Say you have a tyre style, say a balloon, then it has a name, say Big Apple. Within the Big Apple name there are several carcass styles, and they may have separate model numbers, and several tread styles, more model numbers in conjunction with the carcass styles. Before you give a retailer your money, study the Schwalbe catalogue carefully to ascertain what you get under each number, and the variants within it, because I don't think Schwalbe necessarily gives each tread compound a different number (the best, longest lasting and most expensive compound is called "Performance" and there are two cheaper and less-long-lasting types as well). Dealers don't even have to be malicious or greedy to sell something at the highest price justified by the prestigious name (Big Apple, Marathon Plus) when it is fact not the very best sold under that name. Some boutique enhancements, like coloured tyres, are available in some ranges only at the top, in others only in the cheapest compound. Schwalbe's product range was much simpler and easier to understand in years gone by. Still, they make the best tyres, so it is worth a little effort to understand precisely what you're getting from the retailer's hand in return for your money. Check the marketing name, the type number (HIS 308), the protection class (Kevlar, Aramid, some plus a rubber layer like the Marathon Plus) and the compound carefully in all price comparisons of Schwalbe tyres, to ensure you're pricing apples against apples and not Faberge eggs.
You'll find mistakes are rarely made in favour of the customer...