AZ has recently changed its domestic flights booking class. For ex. O class is cheaper than R class (domestic) but for FB mileage earning O gives 50% miles and R: 0%. On european segments R class is cheaper than O and gives no miles.

I've tried to explain than to the FB person on the phone, asking if/when there's going to be an update on FB rules regarding AZ domestic flights but got a kind of "computer says no" answer.

Therefore enjoy the lowest fare on AZ domestic until FB finds out that promo fares let us earn miles!