Originally Posted by
FlyingDentist
LH may be taking a more cautious view - or betting they can sell more J to connecting traffic via their hubs and thus make more money per square foot of cabin.
Maybe the cost of improving the 'old' F, which is a poor F, with the new F, is not justified on many of their routes, especially if they are fitting the proper, flat J in (most LH Js are not proper flat J).