Not saying its right or wrong but this is nothing new with Airbus..... unlike Boeing who over engineer everything....Airbus have a much more active debate between the stress and weight departments at the design stage. End result lighter aircraft...sometimes require the rib feet mod (but still a lighter aircraft than had they gone down the Boeing route). This happened on the A300...will happen again on the next Airbus.... they obviously consider the big picture cost benfit analysis works for everyone.