The six new orders are in fact converted options from the 50/50 order, the -600 may be a typo for more -700s or 800s. There was never any mention of converting to -600s in the original announcement, just -800s which is why it caught my eye. And yes, the -600 is still being built, WestJet Canada just took delivery of their first one. Air Algerie, Tunis Air, Lauda/Austrian and SAS are among current -600 operators.