That's right - smooths get more handling yet, multiple sandings, staining, (possibly more sanding), polishing etc. Shaping has to be perfect, grain has to hold up. One little slip of the file and that smooth is now a sandblast! Even buying very good briar, which Castello for example does, you don't get smooth after smooth. If half the production is smooths that would be pretty good.
Factory briar.... you run a bag full of ebauchons of shape A and quality P through the machine heads, and see what comes out. You pick the best ones and make them your "high end" series, you take the worst ones and rusticate quickly and sell 'em cheap. And that's why a rustic Peterson is 90 bucks and a rustic Castello is 300. The Castello started as better stuff, got handled a lot more, has a far nicer texture and finish, is one of a kind and ... naturally costs 3 times more. Castello is a manufacturer, but basically not a factory in that sense, right? Like, they make 20 pipes a day if they are flying, and Peterson makes 500 (annual distribution of some 100,000 units).